You searched for subject:(High harmonic generation).
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University of Ottawa
1.
A, Kazi.
Nano-engineering of Strong Field Processes in Solids
.
Degree: 2016, University of Ottawa
URL: http://hdl.handle.net/10393/35101 
► We investigate ionization and high harmonic generation (HHG) from the interaction of a mid infra-red laser pulse with a solid state system confined to nano-dimensions.…
(more)
▼ We investigate ionization and high harmonic generation (HHG) from the interaction of a mid infra-red laser pulse with a solid state system confined to nano-dimensions. The theory of strong field processes in solids is developed for confined quantum systems in general. Here it is applied to two-dimensional quantum wires with a driving field linearly polarised along the axis of the wires. Our findings indicate that that we are able to control the ionization and high-harmonic output by altering the width of the wire. Control of ionization leads to an increased damage threshold which has important implications for nano-engineering and realizing all solid state coherent XUV sources.
Subjects/Keywords: high-harmonic-generation;
quantum-wire
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APA (6th Edition):
A, K. (2016). Nano-engineering of Strong Field Processes in Solids
. (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/35101
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
A, Kazi. “Nano-engineering of Strong Field Processes in Solids
.” 2016. Thesis, University of Ottawa. Accessed April 16, 2021.
http://hdl.handle.net/10393/35101.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
A, Kazi. “Nano-engineering of Strong Field Processes in Solids
.” 2016. Web. 16 Apr 2021.
Vancouver:
A K. Nano-engineering of Strong Field Processes in Solids
. [Internet] [Thesis]. University of Ottawa; 2016. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/10393/35101.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
A K. Nano-engineering of Strong Field Processes in Solids
. [Thesis]. University of Ottawa; 2016. Available from: http://hdl.handle.net/10393/35101
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Louisiana State University
2.
Wilson, Benjamin Parker.
Investigating the Photorecombination Dynamics in Molecular High-Harmonic Spectra.
Degree: PhD, Chemistry, 2015, Louisiana State University
URL: etd-03312015-204624
;
https://digitalcommons.lsu.edu/gradschool_dissertations/2210
► The work presented in this dissertation will relate the photorecombination dynamics to photoionization dynamics in SF6 utilizing the self-probing mechanism, high harmonic generation (HHG). This…
(more)
▼ The work presented in this dissertation will relate the photorecombination dynamics to photoionization dynamics in SF6 utilizing the self-probing mechanism, high harmonic generation (HHG). This work specifically aims to establish parameters for which the comparison is applicable and the macroscopic complications inherent in HHG do not interfere with the extraction of dynamic information. The first part of this work established the macroscopic experimental apparatus necessary for consistent spectroscopic observation. It is shown that using a gas jet that is an order of magnitude shorter than the Rayleigh length of the driving laser results in more consistent harmonic spatial profiles and location of spectroscopic features. The observation of photorecombination dynamic in HHG is extended to shape resonances in SF6 with a focus on separating the effects of phase matching from photorecombination. This is accomplished by varying the laser parameters including the location of the focal point with respect to the center of the gas jet and altering the strength of the electric field. This process allowed us to observe two high energy shape resonances in the HHG spectrum of SF6 and map the appropriate parameters at which our experimental results confirm theoretical calculations based on the quantitative rescattering theory conducted by collaborators at Texas A&M University. The shape resonance was then probed by adding ellipticity to the fundamental in order to determine if there was information related to the angular dependence of the shape resonance that could be extracted in a way unique to HHG.
Subjects/Keywords: High Harmonic Generation; Spectroscopy
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APA (6th Edition):
Wilson, B. P. (2015). Investigating the Photorecombination Dynamics in Molecular High-Harmonic Spectra. (Doctoral Dissertation). Louisiana State University. Retrieved from etd-03312015-204624 ; https://digitalcommons.lsu.edu/gradschool_dissertations/2210
Chicago Manual of Style (16th Edition):
Wilson, Benjamin Parker. “Investigating the Photorecombination Dynamics in Molecular High-Harmonic Spectra.” 2015. Doctoral Dissertation, Louisiana State University. Accessed April 16, 2021.
etd-03312015-204624 ; https://digitalcommons.lsu.edu/gradschool_dissertations/2210.
MLA Handbook (7th Edition):
Wilson, Benjamin Parker. “Investigating the Photorecombination Dynamics in Molecular High-Harmonic Spectra.” 2015. Web. 16 Apr 2021.
Vancouver:
Wilson BP. Investigating the Photorecombination Dynamics in Molecular High-Harmonic Spectra. [Internet] [Doctoral dissertation]. Louisiana State University; 2015. [cited 2021 Apr 16].
Available from: etd-03312015-204624 ; https://digitalcommons.lsu.edu/gradschool_dissertations/2210.
Council of Science Editors:
Wilson BP. Investigating the Photorecombination Dynamics in Molecular High-Harmonic Spectra. [Doctoral Dissertation]. Louisiana State University; 2015. Available from: etd-03312015-204624 ; https://digitalcommons.lsu.edu/gradschool_dissertations/2210
Louisiana State University
3.
Wu, Mengxi.
Attosecond Transient Absorption in Gases and High Harmonic Generation in Solids.
Degree: PhD, Physical Sciences and Mathematics, 2015, Louisiana State University
URL: etd-07042015-191603
;
https://digitalcommons.lsu.edu/gradschool_dissertations/3321
► We present a theoretical study of attosecond transient absorption in gases and high harmonic generation in solids. In this thesis, different features in the attosecond…
(more)
▼ We present a theoretical study of attosecond transient absorption in gases and high harmonic generation in solids. In this thesis, different features in the attosecond transient absorption laser-dressed spectrum are studied, including features near bright (dipole allowed) atomic states and features that appear approximately one or two laser photons away from the bright states due to the laser-induced coupling to dark (non-dipole allowed) states. The calculations are carried out using both numerical and analytic solutions to the time-dependent Schrödinger equation (TDSE). From these solutions, several models of time-dependent absorption and electron dynamics at the femtosecond time scale are presented. We discuss transient absorption in two different regimes: a resonant regime when the dressing field resonantly couples bright and dark states; and a non-resonant regime when the dressed states are detuned. Moreover, a Floquet picture of the transient absorption process is presented, in which the different features in the absorption spectrum are explained as the Floquet states induced by the strong probe pulse. We demonstrate that this Floquet picture applies even though dressing field lasts only a few cycles. We also present a theoretical study of high harmonic generation (HHG) by Bloch electrons in a model transparent solid. This model applies to the recent experiments in ZnO. We solve the TDSE using a velocity gauge numerical method and the resulting harmonic spectrum exhibits a plateau due to the coupling of the valence band to the first conduction band. The energy cutoff of the plateau scales linearly with field strength, which agrees with the ZnO experiment. To facilitate the analysis of the time-frequency characteristics of the emitted harmonics, the TDSE is also solved in the so-called Houston basis which allows the separation of the interband and intraband contributions to the time-dependent current. The interband and intraband transitions are shown to correspond to diabatic and adiabatic dynamics of the system, respectively. The contributions from interband and intraband display very different time-frequency characteristics, which can potentially be used as an experimental signature of the intraband and interband dynamics.
Subjects/Keywords: High harmonic generation; transient absorption; ultrafast physics
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APA (6th Edition):
Wu, M. (2015). Attosecond Transient Absorption in Gases and High Harmonic Generation in Solids. (Doctoral Dissertation). Louisiana State University. Retrieved from etd-07042015-191603 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3321
Chicago Manual of Style (16th Edition):
Wu, Mengxi. “Attosecond Transient Absorption in Gases and High Harmonic Generation in Solids.” 2015. Doctoral Dissertation, Louisiana State University. Accessed April 16, 2021.
etd-07042015-191603 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3321.
MLA Handbook (7th Edition):
Wu, Mengxi. “Attosecond Transient Absorption in Gases and High Harmonic Generation in Solids.” 2015. Web. 16 Apr 2021.
Vancouver:
Wu M. Attosecond Transient Absorption in Gases and High Harmonic Generation in Solids. [Internet] [Doctoral dissertation]. Louisiana State University; 2015. [cited 2021 Apr 16].
Available from: etd-07042015-191603 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3321.
Council of Science Editors:
Wu M. Attosecond Transient Absorption in Gases and High Harmonic Generation in Solids. [Doctoral Dissertation]. Louisiana State University; 2015. Available from: etd-07042015-191603 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3321
4.
Schoun, Stephen Bradley.
Attosecond High-Harmonic Spectroscopy of Atoms and Molecules
Using Mid-Infrared Sources.
Degree: PhD, Physics, 2015, The Ohio State University
URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1436853089
► The amplitude and phase of the complex photoionization/photorecombination dipole matrix element of atoms and simple linear molecules is measured with sub-femtosecond time resolution and sub-electronvolt…
(more)
▼ The amplitude and phase of the complex
photoionization/photorecombination dipole matrix element of atoms
and simple linear molecules is measured with sub-femtosecond time
resolution and sub-electronvolt spectral resolution using
High
Harmonic Spectroscopy (HHS). The first known measurement of the
dipole phase jump at a Cooper minimum is reported for the
<i>3p</i> orbital of argon. Also, the angle-dependent
dipole of nitrogen is measured using rotationally-aligned molecular
ensembles. In contrast with previous studies, which were limited by
traditional shorter-wavelength near-infrared laser sources, only a
single orbital is sufficient to explain the nitrogen results, which
are in excellent agreement with accurate theoretical
scattering-wave dipole calculations. All of these experiments
benefit from the extended extreme-ultraviolet cutoff, and improved
spectral resolution, afforded by the use of long-wavelength
mid-infrared driving laser sources.This work extends our
understanding of the interaction of light and matter on the
timescale of the electron's motion, the attosecond (1 as =
10
-18 s). The experimental results presented
here lend credence to the methodology of molecular self-imaging by
laser-induced ionization and recombination of a molecule's own
electron. The successes and limitations of HHS as a tool for
ultrafast atomic and molecular imaging are discussed. Finally, the
feasibility is examined of using HHS to measure the temporal
evolution of complicated chemical dynamics with attosecond
precision.
Advisors/Committee Members: DiMauro, Louis (Advisor).
Subjects/Keywords: Physics; attosecond; RABBITT; high-order harmonic generation; high harmonic generation, HHG; high harmonic spectroscopy; HHS; XUV; photoionization
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APA ·
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APA (6th Edition):
Schoun, S. B. (2015). Attosecond High-Harmonic Spectroscopy of Atoms and Molecules
Using Mid-Infrared Sources. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1436853089
Chicago Manual of Style (16th Edition):
Schoun, Stephen Bradley. “Attosecond High-Harmonic Spectroscopy of Atoms and Molecules
Using Mid-Infrared Sources.” 2015. Doctoral Dissertation, The Ohio State University. Accessed April 16, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1436853089.
MLA Handbook (7th Edition):
Schoun, Stephen Bradley. “Attosecond High-Harmonic Spectroscopy of Atoms and Molecules
Using Mid-Infrared Sources.” 2015. Web. 16 Apr 2021.
Vancouver:
Schoun SB. Attosecond High-Harmonic Spectroscopy of Atoms and Molecules
Using Mid-Infrared Sources. [Internet] [Doctoral dissertation]. The Ohio State University; 2015. [cited 2021 Apr 16].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1436853089.
Council of Science Editors:
Schoun SB. Attosecond High-Harmonic Spectroscopy of Atoms and Molecules
Using Mid-Infrared Sources. [Doctoral Dissertation]. The Ohio State University; 2015. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1436853089
University of Lund
5.
Mikaelsson, Sara.
Short Attosecond Pulse Trains at High Repetition Rates
for Novel Pump-Probe and Coincidence Studies.
Degree: 2021, University of Lund
URL: https://lup.lub.lu.se/record/d64ff897-8437-4145-a65a-75e3952a2fc4
;
https://portal.research.lu.se/ws/files/89197604/Kappa_SMikaelsson.pdf
► This work aims at studying photoionization dynamics from atoms and surfaces at attose time scales. The work was based on development and applications of a…
(more)
▼ This work aims at studying photoionization dynamics
from atoms and surfaces at attose time scales. The work was based
on development and applications of a high repetition rate
High-order Harmonic Generation (HHG) light source that utilizes
Optical Parametric Amplification (OPA) laser technology. The laser
system delivers few-cycle pulses in the near infrared (IR) at a
repetition rate of 200 kHz. Through the use of advanced pulse
characterization techniques, the pulse quality was kept high in
order to ensure efficient HHG at relatively low pulse energies. In
the HHG process, a short extreme ultraviolet (XUV) light pulse of
attosecond duration is produced with every half cycle of the
driving field.When performing HHG with driving pulses in the
few-cycle regime, a short attosecond pulse train consisting of only
a handful pulses is generated. The spectral properties and temporal
structure of the HHG radiation was explained in terms of
interference between attosecond pulses. The number of pulses can be
controlled with the Carrier-to-Envelope Phase (CEP). The short
pulse trains were used together with a weak IR field for two-color
photoionization, measured with a 3D momentum imaging spectrometer.
The angle-resolved photoionization spectra are found to be
asymmetric, and behave distinctly different depending primarily on
the number of pulses that are used for ionization. In the case when
two pulses are used, the electron peaks are shifted, but when the
number is increased to three, additional peaks appear. This was
explained using an attosecond time-slit interference model.The
coincidence capabilities of the photoelectron spectrometer were
utilized to measure single-photon double-ionization of helium for
the first time with an HHG source. This challenging measurement
combines the coincidence and imaging properties of the spectrometer
with the efficient generation of high harmonics, and is only
possible due to the high repetition rate of the source. The full
Triple Differential Cross Section (TDCS) was obtained for a range
of energies. Additionally, the IR light source was used for surface
science applications, which benefit strongly from a high repetition
rate. Light-wave driven currents in semiconductor materials were
measured at a higher repetition rate and with longer pulses than
reported previously. Plasmon dynamics in gold nanosponges and
induced at the edges of thin layers of the Transition Metal
Dichalcogenide (TMD) WSe2 were studied.
Subjects/Keywords: Atom and Molecular Physics and Optics; Attosecond; High-Order Harmonic Generation; Photoionization; Attosecond; High-Order Harmonic Generation; Photoionization
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APA ·
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Manager
APA (6th Edition):
Mikaelsson, S. (2021). Short Attosecond Pulse Trains at High Repetition Rates
for Novel Pump-Probe and Coincidence Studies. (Doctoral Dissertation). University of Lund. Retrieved from https://lup.lub.lu.se/record/d64ff897-8437-4145-a65a-75e3952a2fc4 ; https://portal.research.lu.se/ws/files/89197604/Kappa_SMikaelsson.pdf
Chicago Manual of Style (16th Edition):
Mikaelsson, Sara. “Short Attosecond Pulse Trains at High Repetition Rates
for Novel Pump-Probe and Coincidence Studies.” 2021. Doctoral Dissertation, University of Lund. Accessed April 16, 2021.
https://lup.lub.lu.se/record/d64ff897-8437-4145-a65a-75e3952a2fc4 ; https://portal.research.lu.se/ws/files/89197604/Kappa_SMikaelsson.pdf.
MLA Handbook (7th Edition):
Mikaelsson, Sara. “Short Attosecond Pulse Trains at High Repetition Rates
for Novel Pump-Probe and Coincidence Studies.” 2021. Web. 16 Apr 2021.
Vancouver:
Mikaelsson S. Short Attosecond Pulse Trains at High Repetition Rates
for Novel Pump-Probe and Coincidence Studies. [Internet] [Doctoral dissertation]. University of Lund; 2021. [cited 2021 Apr 16].
Available from: https://lup.lub.lu.se/record/d64ff897-8437-4145-a65a-75e3952a2fc4 ; https://portal.research.lu.se/ws/files/89197604/Kappa_SMikaelsson.pdf.
Council of Science Editors:
Mikaelsson S. Short Attosecond Pulse Trains at High Repetition Rates
for Novel Pump-Probe and Coincidence Studies. [Doctoral Dissertation]. University of Lund; 2021. Available from: https://lup.lub.lu.se/record/d64ff897-8437-4145-a65a-75e3952a2fc4 ; https://portal.research.lu.se/ws/files/89197604/Kappa_SMikaelsson.pdf
University of California – Berkeley
6.
Abel, Mark Joseph.
Attosecond X-Ray Pulses for Molecular Electronic Dynamics.
Degree: Chemistry, 2010, University of California – Berkeley
URL: http://www.escholarship.org/uc/item/97w0k12j
► Attosecond pulses are opening a wide new field on the border of chemistry and physics. They offer the opportunity to initiate and probe electronic rearrangement…
(more)
▼ Attosecond pulses are opening a wide new field on the border of chemistry and physics. They offer the opportunity to initiate and probe electronic rearrangement of atoms, molecules, solids and clusters on the natural timescale of the electron motion. This thesis is about making and measuring attosecond pulses, with the ultimate goal of applying attosecond spectroscopy to molecules. In chapter 1, attosecond spectroscopy is reviewed in general. The applications of attosecond pulses to atoms and molecules, including successful experiments and theoretical predictions, are discussed. In chapter 2, techniques for making and measuring attosecond radiation are presented. This chapter focuses on high harmonic generation from tabletop laser sources, since synchrotron- and free-electron laser-based techniques are not yet experimentally demonstrated. Chapters 3 and 4 discuss in detail the laboratory setup for attosecond pulse generation, including the laser source, optical diagnostics, and attosecond delay line. The attosecond control of free electron motion with few-cycle laser pulses is presented in chapter 5. There, the carrier-envelope phase (CEP), and thus the attosecond temporal evolution of the laser field, leads to quantum interferences between free electron wavefunctions and lends control over the direction of electron emission. Attosecond pulse production is achieved in chapter 6 by gating harmonic generation on the leading edge of the driving laser pulse. The gate mechanism is shown to rely on the macroscopic ionization of the harmonic generation medium. This final chapter also demonstrates a new technique for assessing attosecond pulse temporal structure based on the inversion of the driving laser field in the laboratory frame of reference, called CEP-scanning.
Subjects/Keywords: Chemistry, Physical; Physics, Optics; attosecond; carrier-envelope phase; high harmonic generation
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APA (6th Edition):
Abel, M. J. (2010). Attosecond X-Ray Pulses for Molecular Electronic Dynamics. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/97w0k12j
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Abel, Mark Joseph. “Attosecond X-Ray Pulses for Molecular Electronic Dynamics.” 2010. Thesis, University of California – Berkeley. Accessed April 16, 2021.
http://www.escholarship.org/uc/item/97w0k12j.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Abel, Mark Joseph. “Attosecond X-Ray Pulses for Molecular Electronic Dynamics.” 2010. Web. 16 Apr 2021.
Vancouver:
Abel MJ. Attosecond X-Ray Pulses for Molecular Electronic Dynamics. [Internet] [Thesis]. University of California – Berkeley; 2010. [cited 2021 Apr 16].
Available from: http://www.escholarship.org/uc/item/97w0k12j.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Abel MJ. Attosecond X-Ray Pulses for Molecular Electronic Dynamics. [Thesis]. University of California – Berkeley; 2010. Available from: http://www.escholarship.org/uc/item/97w0k12j
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Ottawa
7.
Wong, Michael C. H.
High Harmonic Spectroscopy of Complex Molecules
.
Degree: 2014, University of Ottawa
URL: http://hdl.handle.net/10393/31640
► Advancements in spectroscopy rely on the improvement of two fundamental characteristics: spatial and temporal resolutions. High harmonic spectroscopy (HHS) is an emerging technology that promises…
(more)
▼ Advancements in spectroscopy rely on the improvement of two fundamental characteristics: spatial and temporal resolutions. High harmonic spectroscopy (HHS) is an emerging technology that promises the capability of studying the fastest processes that exist today: electronic motion with angstrom spatial and attosecond temporal resolution. HHS is based on the process of high harmonic generation (HHG) which arises from the nonlinear interaction between an intense, infrared laser pulse and an atomic or molecular gaseous medium, producing coherent, attosecond-duration bursts of extreme ultraviolet (XUV) light.
In order to utilize the attosecond pulses for spectroscopic measurements, it is necessary to improve the conversion efficiency of HHG. Chapter 2 of this thesis describes the improvements we make to the HHG source in order to obtain high XUV photon flux and we report on the nonlinear ionization of atomic systems using these pulses in Chapter 6.
In Chapters 3 - 5, we describe several HHG experiments in complex, polyatomic molecules in order to promote the use of HHS as a general spectroscopic tool. Amplitude modulations in high harmonic spectra of complex molecules can be attributed to several types of interference conditions that depend on a system's molecular or electronic structure such as recombination with multiple centres or dynamical interference from multi-orbital contributions to ionization. Our results demonstrate the capability of HHS to extract useful information on molecular and electronic structure from large, polyatomic molecules directly from their high harmonic spectra. Furthermore, we use HHS to investigate the suppression of ionization in complex molecules due to quantum
destructive interference during ionization as well as the distinguishability of emitted harmonic spectra from molecular isomers.
Chapter 6 explores the study of multi-electron dynamics in complex molecules using XUV multiphoton ionization of atoms and molecules as well as the ionization and fragmentation of C60 which has hundreds of delocalized valence electrons. This thesis also describes the author's role in the design and fabrication of a time-of-
flight mass spectrometer (Section 6.1) as well as an HHG detector system (Appendix A).
Subjects/Keywords: High harmonic generation;
Strong-field physics;
Multi-electron dynamics;
Multiphoton ionization
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APA ·
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Manager
APA (6th Edition):
Wong, M. C. H. (2014). High Harmonic Spectroscopy of Complex Molecules
. (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/31640
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Wong, Michael C H. “High Harmonic Spectroscopy of Complex Molecules
.” 2014. Thesis, University of Ottawa. Accessed April 16, 2021.
http://hdl.handle.net/10393/31640.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Wong, Michael C H. “High Harmonic Spectroscopy of Complex Molecules
.” 2014. Web. 16 Apr 2021.
Vancouver:
Wong MCH. High Harmonic Spectroscopy of Complex Molecules
. [Internet] [Thesis]. University of Ottawa; 2014. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/10393/31640.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Wong MCH. High Harmonic Spectroscopy of Complex Molecules
. [Thesis]. University of Ottawa; 2014. Available from: http://hdl.handle.net/10393/31640
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Colorado
8.
La-o-vorakiat, Chan.
Element-Selective Ultrafast Magnetization Dynamics with a Tabletop Light Source.
Degree: PhD, Physics, 2011, University of Colorado
URL: https://scholar.colorado.edu/phys_gradetds/46
► Next-generation hard-disk drives will require smaller magnetic bits and faster magnetization switching; hence, better understanding of nanoscale magnetic material is one of the key…
(more)
▼ Next-
generation hard-disk drives will require smaller magnetic bits and faster magnetization switching; hence, better understanding of nanoscale magnetic material is one of the key factors in developing of these devices. Here, I present the first ultrafast magnetization dynamics studies by use of extreme ultraviolet radiation from a tabletop
high-
harmonic generation source. This new probing technique offers three advantages over conventional ones: ultrafast time resolution, element selectivity, and the tabletop size.
I report three experiments showing that
high harmonics are a powerful tool for probing magnetization in magnetic materials. First, our group measures simultaneously the magnetizations of Ni and Fe in Permalloy using the transverse magneto-optical Kerr effect. Second, we study laser-induced demagnetization dynamics in two ferromagnetic alloys: Permalloy and Permalloy-Cu. Contrary to a common expectation that the dynamics in strong exchange-coupled alloys would be identical, we discover that the magnetization of Fe decays earlier than that of Ni during the first 60 fs. To explain this delay, we propose a simple model incorporating a finite exchange-time factor into the magnetization rate equations. Finally, to confirm the observed sequence of dynamics in alloys, we conduct the magnetization study of elemental Fe and Ni with identical experimental conditions. The results indicate that the order of demagnetizations in the elemental forms is the same as that in Permalloy: Fe demagnetizes faster than Ni does.
Advisors/Committee Members: Henry C. Kapteyn, Margaret M. Murnane, Thomas J. Silva.
Subjects/Keywords: Demagnetization Dynamics; High-harmonic Generation; Magnetism; Ultrafast; Condensed Matter Physics
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APA (6th Edition):
La-o-vorakiat, C. (2011). Element-Selective Ultrafast Magnetization Dynamics with a Tabletop Light Source. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/phys_gradetds/46
Chicago Manual of Style (16th Edition):
La-o-vorakiat, Chan. “Element-Selective Ultrafast Magnetization Dynamics with a Tabletop Light Source.” 2011. Doctoral Dissertation, University of Colorado. Accessed April 16, 2021.
https://scholar.colorado.edu/phys_gradetds/46.
MLA Handbook (7th Edition):
La-o-vorakiat, Chan. “Element-Selective Ultrafast Magnetization Dynamics with a Tabletop Light Source.” 2011. Web. 16 Apr 2021.
Vancouver:
La-o-vorakiat C. Element-Selective Ultrafast Magnetization Dynamics with a Tabletop Light Source. [Internet] [Doctoral dissertation]. University of Colorado; 2011. [cited 2021 Apr 16].
Available from: https://scholar.colorado.edu/phys_gradetds/46.
Council of Science Editors:
La-o-vorakiat C. Element-Selective Ultrafast Magnetization Dynamics with a Tabletop Light Source. [Doctoral Dissertation]. University of Colorado; 2011. Available from: https://scholar.colorado.edu/phys_gradetds/46
University of Colorado
9.
Yost, Dylan.
Development of an Extreme Ultraviolet Frequency Comb for Precision Spectroscopy.
Degree: PhD, Physics, 2011, University of Colorado
URL: https://scholar.colorado.edu/phys_gradetds/47
► We describe an extreme-ultraviolet frequency comb produced via high repetition rate, intracavity high harmonic generation. The experimental apparatus consists of a high power frequency…
(more)
▼ We describe an extreme-ultraviolet frequency comb produced via
high repetition rate, intracavity
high harmonic generation. The experimental apparatus consists of a
high power frequency comb of 80 W average power, which excites a robust femtosecond enhancement cavity. On resonance, the enhancement cavity contains >8 kW of average power and is capable of driving the
high harmonic process at a repetition rate of 154 MHz producing a frequency comb. More than 200 microwatts of XUV power is generated in each
harmonic. While it is difficult to build a continuous wave laser below 100 nm, this source functions as millions of intrinsically calibrated narrow-linewidth sources in the XUV. With this unique radiation source, we were able to conduct
high resolution, direct frequency comb spectroscopy on neutral argon atoms at a wavelength of 82 nm. This measurement demonstrates the efficacy of this technique for precision measurement.
Advisors/Committee Members: Jun Ye, Steven Cundi, Eric A Cornell.
Subjects/Keywords: Extreme Ultraviolet; High harmonic generation; Spectroscopy; Atomic, Molecular and Optical Physics
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APA (6th Edition):
Yost, D. (2011). Development of an Extreme Ultraviolet Frequency Comb for Precision Spectroscopy. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/phys_gradetds/47
Chicago Manual of Style (16th Edition):
Yost, Dylan. “Development of an Extreme Ultraviolet Frequency Comb for Precision Spectroscopy.” 2011. Doctoral Dissertation, University of Colorado. Accessed April 16, 2021.
https://scholar.colorado.edu/phys_gradetds/47.
MLA Handbook (7th Edition):
Yost, Dylan. “Development of an Extreme Ultraviolet Frequency Comb for Precision Spectroscopy.” 2011. Web. 16 Apr 2021.
Vancouver:
Yost D. Development of an Extreme Ultraviolet Frequency Comb for Precision Spectroscopy. [Internet] [Doctoral dissertation]. University of Colorado; 2011. [cited 2021 Apr 16].
Available from: https://scholar.colorado.edu/phys_gradetds/47.
Council of Science Editors:
Yost D. Development of an Extreme Ultraviolet Frequency Comb for Precision Spectroscopy. [Doctoral Dissertation]. University of Colorado; 2011. Available from: https://scholar.colorado.edu/phys_gradetds/47
University of Colorado
10.
Chen, Cong.
Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy.
Degree: PhD, 2017, University of Colorado
URL: https://scholar.colorado.edu/phys_gradetds/205
► Recent advances in the generation and control of attosecond light pulses have opened up new opportunities for the real-time observation of sub-femtosecond (1 fs…
(more)
▼ Recent advances in the
generation and control of attosecond light pulses have opened up new opportunities for the real-time observation of sub-femtosecond (1 fs = 10
-15 s) electron dynamics in gases and solids. Combining attosecond light pulses with angle-resolved photoelectron spectroscopy (atto-ARPES) provides a powerful new technique to study the influence of material band structure on attosecond electron dynamics in materials. Electron dynamics that are only now accessible include the lifetime of far-above-bandgap excited electronic states, as well as fundamental electron interactions such as scattering and screening. In addition, the same atto-ARPES technique can also be used to measure the temporal structure of complex coherent light fields. In this thesis, I present four experiments utilizing atto-ARPES to provide new insights into the
generation and characterization of attosecond light pulses, as well as the attosecond electron dynamics in transition metals. First, I describe a new method to extend attosecond metrology techniques to the reconstruction of circularly polarized attosecond light pulses for the first time. Second, I show that by driving
high harmonics with a two-color linearly polarized laser field, quasi-isolated attosecond pulses are generated because the phase matching window is confined. Third, I present the first measurement of lifetimes for photoelectrons that are born into free-electron-like states compared with those that are excited into unoccupied excited states in the band structure of a material (Ni(111)). The finite excited-state lifetime causes a ≈200 as delay in the emission of photoelectrons. Finally, I describe direct time-domain studies of electron-electron interactions in transition metals with both simple and complex Fermi surfaces. In particular, I show the influence of electron-electron scattering and screening on the lifetime of photoelectrons.
Advisors/Committee Members: Margaret M. Murnane, Henry C. Kapteyn, Andreas Becker, Xiaobo Yin, W. Carl Lineberger.
Subjects/Keywords: attosecond; electron dynamics; EUV; high harmonic generation; photoemission; ultrafast; Physics
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APA (6th Edition):
Chen, C. (2017). Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/phys_gradetds/205
Chicago Manual of Style (16th Edition):
Chen, Cong. “Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy.” 2017. Doctoral Dissertation, University of Colorado. Accessed April 16, 2021.
https://scholar.colorado.edu/phys_gradetds/205.
MLA Handbook (7th Edition):
Chen, Cong. “Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy.” 2017. Web. 16 Apr 2021.
Vancouver:
Chen C. Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy. [Internet] [Doctoral dissertation]. University of Colorado; 2017. [cited 2021 Apr 16].
Available from: https://scholar.colorado.edu/phys_gradetds/205.
Council of Science Editors:
Chen C. Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy. [Doctoral Dissertation]. University of Colorado; 2017. Available from: https://scholar.colorado.edu/phys_gradetds/205
University of Oxford
11.
Liu, Lewis.
Polarisation controlled quasi-phase matching of high harmonic generation.
Degree: PhD, 2014, University of Oxford
URL: http://ora.ox.ac.uk/objects/uuid:8a5c65ae-d099-440e-beaa-6e514b4545dc
;
https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686941
► This thesis focuses on the development of high harmonic generation (HHG) by using polarisation controlled quasi-phase matching QPM as well as related topics. A new…
(more)
▼ This thesis focuses on the development of high harmonic generation (HHG) by using polarisation controlled quasi-phase matching QPM as well as related topics. A new class of QPM techniques called polarisation-controlled QPM is introduced where linear or circlar birefringence enables the modulation of the driving field's polarisation state called polarisation-beating QPM (PBQPM) for linear birefringence and optical rotation QPM (ORQPM) for circular birefringence respectively. PBQPM uses a linear birefringence to modulate periodically the driving pulse between linear and circular/elliptical polarisation states. Because elliptical or circular polarisation of the driving pulse suppresses harmonic generation, by appropriately matching the beat length of the driving field's polarisation state to the coherence length of the harmonic generation, QPM can be achieved. In the second technique, ORQPM, propagation of the driving radiation in a system exhibiting circular birefringence causes its plane of polarisation to rotate; by appropriately matching the period of rotation to the coherence length, it is possible to avoid destructive interference of the generated radiation. Not only does ORQPM have similar enhancements as true-phase matching, it is also the first proposed QPM source for circularly polarised high harmonics. The importance of phase modulation in QPM, especially relating to modebeating in hollow-core waveguides where harmonics is being generated are also explored theoretically. Based on this, a novel technique for analyzing random phase matching using a continuous phase-diffusion treatment has been developed; theoretical analytical models are shown to produce excellent agreement with simulations. It is further shown that random phase matching may be responsible for additional broadening of the high harmonic spectrum, especially at higher harmonic orders. Because mode and polarisation control is central to polarisation-controlled QPM, four waveguide mode decomposition techniques from single shot CCD data have been developed. The extraction of phase and coupling coefficients are demonstrated experimentally. A novel analytical general solution for the phase introduced by a phase-only spatial light modulator to generate a given far-field phase and amplitude was developed. The solution was demonstrated experimentally and shown to enable excellent control of the far-field amplitude and phase. Finally, circular and linear birefringent waveguides were explored. Analytic solutions to rectangular birefringent hollow-core waveguides were developed and some initial demonstration experiments were performed.
Subjects/Keywords: 621.381; Atomic and laser physics; high harmonic generation; waveguides
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APA (6th Edition):
Liu, L. (2014). Polarisation controlled quasi-phase matching of high harmonic generation. (Doctoral Dissertation). University of Oxford. Retrieved from http://ora.ox.ac.uk/objects/uuid:8a5c65ae-d099-440e-beaa-6e514b4545dc ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686941
Chicago Manual of Style (16th Edition):
Liu, Lewis. “Polarisation controlled quasi-phase matching of high harmonic generation.” 2014. Doctoral Dissertation, University of Oxford. Accessed April 16, 2021.
http://ora.ox.ac.uk/objects/uuid:8a5c65ae-d099-440e-beaa-6e514b4545dc ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686941.
MLA Handbook (7th Edition):
Liu, Lewis. “Polarisation controlled quasi-phase matching of high harmonic generation.” 2014. Web. 16 Apr 2021.
Vancouver:
Liu L. Polarisation controlled quasi-phase matching of high harmonic generation. [Internet] [Doctoral dissertation]. University of Oxford; 2014. [cited 2021 Apr 16].
Available from: http://ora.ox.ac.uk/objects/uuid:8a5c65ae-d099-440e-beaa-6e514b4545dc ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686941.
Council of Science Editors:
Liu L. Polarisation controlled quasi-phase matching of high harmonic generation. [Doctoral Dissertation]. University of Oxford; 2014. Available from: http://ora.ox.ac.uk/objects/uuid:8a5c65ae-d099-440e-beaa-6e514b4545dc ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686941
12.
Chatziathanasiou, Stefanos.
Μελέτη φαινομένων συμβολής κβαντικών διαδρομών ηλεκτρονίων από ευθυγραμμισμένα μόρια σε ισχυρά πεδία laser και παραγωγή κυκλικά πολωμένης ακτινοβολίας στη φασματική περιοχή του ακραίου υπεριώδους (XUV).
Degree: 2019, University of Crete (UOC); Πανεπιστήμιο Κρήτης
URL: http://hdl.handle.net/10442/hedi/46276
► The aim of the thesis is to unravel the dynamics of the High Harmonic Generation (HHG) process induced in strongly laser driven aligned molecules and…
(more)
▼ The aim of the thesis is to unravel the dynamics of the High Harmonic Generation (HHG) process induced in strongly laser driven aligned molecules and develop a method for the production of circularly polarized ultrashort pulses in the extreme-ultraviolet (XUV) spectral range. Towards these goals we have used the Time Gated Ion Microscopy (IM) technique and a pump-probe arrangement. The former maps the spatial XUV intensity distribution onto a spatial ion distribution (produced in the XUV focal area through a single–XUV– photon ionization process of an atomic gas). The pump–probe arrangement was used to trigger the molecular alignment process and generate the high–harmonics. Initially, in order to calibrate the harmonic generation/detection scheme, we have used only the IM and Argon (Ar) atoms for the generation of high-harmonics. In this experiment we have measured and quantified the influence of spatiotemporal coupling effects in HHG region. After, using N2 molecules and the IM approach in combination with the pump-probe arrangement, we have spatially resolved the interference pattern produced by the spatiotemporal overlap of the harmonics emitted by the short– and long–electron quantum paths, and we have succeeded in measuring in-situ their phase difference and disclose their dependence on molecular alignment. The findings constitute a vital step towards understanding of strong-field molecular physics and the development of a self-referenced attosecond spectroscopy approach. Additionally using the same pump-probe arrangement we demonstrate a method for the generation of circularly polarized XUV radiation using CO2 molecules, a matter which is important for investigating phenomena such as circular dichroism, ultrafast spin dynamics, magnetic microscopy, chirality assignment e.t.c.
Στην παρούσα διδακτορική διατριβή, χρησιμοποιώντας την απεικονιστική μέθοδο του μικροσκοπίου ιόντων χρονικής πύλης (Time Gated Ion Microscopy), μελετήθηκε η διαδικασία της παραγωγής των αρμονικών στην περιοχή της παραγωγής τους. Η μελέτη πραγματοποιήθηκε για αρμονικές που παράγονται από την αλληλεπίδραση ισχυρών IR παλμών λέιζερ με άτομα (Ar) και ευθυγραμμισμένα μόρια αζώτου (N2). Η ευθυγράμμιση των μορίων επιτεύχθηκε με την ανάπτυξη μίας διάταξης άντλησης-ανίχνευσης (pump-probe). Η καταγραφή της χωρικής κατανομής της έντασης των αρμονικών στην περιοχή της παραγωγής τους οδήγησε σε σημαντικά συμπεράσματα τόσο για την εξάρτηση της διαδικασίας παραγωγής των αρμονικών από την σχετική θέση του jet παραγωγής και της δέσμης του IR στην περιοχή της παραγωγής των αρμονικών, όσο και για την δυναμική της ευθυγράμμισης των μορίων. Η ίδια διάταξη χρησιμοποιήθηκε για την παραγωγή XUV ακτινοβολίας με υψηλό βαθμό ελλειπτικότητας από ευθυγραμμισμένα μόρια διοξειδίου του άνθρακα (CO2).
Subjects/Keywords: Παραγωγη αρμονικών υψηλής τάξης; Μοριακή ευθυγράμμιση; High harmonic generation; Molecular alignment
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APA (6th Edition):
Chatziathanasiou, S. (2019). Μελέτη φαινομένων συμβολής κβαντικών διαδρομών ηλεκτρονίων από ευθυγραμμισμένα μόρια σε ισχυρά πεδία laser και παραγωγή κυκλικά πολωμένης ακτινοβολίας στη φασματική περιοχή του ακραίου υπεριώδους (XUV). (Thesis). University of Crete (UOC); Πανεπιστήμιο Κρήτης. Retrieved from http://hdl.handle.net/10442/hedi/46276
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Chatziathanasiou, Stefanos. “Μελέτη φαινομένων συμβολής κβαντικών διαδρομών ηλεκτρονίων από ευθυγραμμισμένα μόρια σε ισχυρά πεδία laser και παραγωγή κυκλικά πολωμένης ακτινοβολίας στη φασματική περιοχή του ακραίου υπεριώδους (XUV).” 2019. Thesis, University of Crete (UOC); Πανεπιστήμιο Κρήτης. Accessed April 16, 2021.
http://hdl.handle.net/10442/hedi/46276.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Chatziathanasiou, Stefanos. “Μελέτη φαινομένων συμβολής κβαντικών διαδρομών ηλεκτρονίων από ευθυγραμμισμένα μόρια σε ισχυρά πεδία laser και παραγωγή κυκλικά πολωμένης ακτινοβολίας στη φασματική περιοχή του ακραίου υπεριώδους (XUV).” 2019. Web. 16 Apr 2021.
Vancouver:
Chatziathanasiou S. Μελέτη φαινομένων συμβολής κβαντικών διαδρομών ηλεκτρονίων από ευθυγραμμισμένα μόρια σε ισχυρά πεδία laser και παραγωγή κυκλικά πολωμένης ακτινοβολίας στη φασματική περιοχή του ακραίου υπεριώδους (XUV). [Internet] [Thesis]. University of Crete (UOC); Πανεπιστήμιο Κρήτης; 2019. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/10442/hedi/46276.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Chatziathanasiou S. Μελέτη φαινομένων συμβολής κβαντικών διαδρομών ηλεκτρονίων από ευθυγραμμισμένα μόρια σε ισχυρά πεδία laser και παραγωγή κυκλικά πολωμένης ακτινοβολίας στη φασματική περιοχή του ακραίου υπεριώδους (XUV). [Thesis]. University of Crete (UOC); Πανεπιστήμιο Κρήτης; 2019. Available from: http://hdl.handle.net/10442/hedi/46276
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Université Catholique de Louvain
13.
Naccarato, Francesco.
First-principles high-throughput study of linear and nonlinear optical materials.
Degree: 2019, Université Catholique de Louvain
URL: http://hdl.handle.net/2078.1/222564
► Nonlinear optical (NLO) processes, such as second harmonic generation (SHG), shift current, and others, play an important role in modern optics, especially in laser-related science…
(more)
▼ Nonlinear optical (NLO) processes, such as second harmonic generation (SHG), shift current, and others, play an important role in modern optics, especially in laser-related science and technology. They are at the core of a wide variety of applications ranging from optoelectronics to medicine. Among the various NLO materials, insulators are particularly important for second-order NLO properties. In particular, only crystals which are non-centrosymmetric can display a non-zero second-order NLO susceptibility. However, given the large number of requirements that a material needs to meet in order to be a good nonlinear optical material, the choice of compounds is drastically limited. Indeed, despite recent progress, a systematic approach to design NLO materials is still lacking. In this work, we conduct a first-principles high-throughput study on a large set of semiconductors for which we computed the linear and nonlinear susceptibility using Density Functional Perturbation Theory. We propose two main approaches for the analysis of the linear and nonlinear optical coefficients: (i) the analysis of the data trend through data mining techniques for the sake of deriving descriptive models, (ii) the screening of the materials collected in our databases to individuate interesting optical materials candidates. For the linear optical properties, our calculations confirm the general trend that the refractive index is roughly inversely proportional to the band gap. In order to explain the large spread in the data distribution, we have found that two descriptors successfully describe materials with relatively high refraction index: (i) a narrow distribution in energy of the optical transitions which brings the average optical gap close to the direct band gap (ii) a large number of transitions around the band edge and/or high dipole matrix elements. For non-centrosymmetric crystals, we perform the calculation of the efficiency of SHG. We observe some materials with particularly high SHG, much stronger than the general relation with the linear refraction index through Miller's rule predicts. We relate the value of Miller's coefficient to geometric factors, i.e., how strongly the crystal deviates from a centrosymmetric one. We also identified interesting materials that show high optical responses for which it would be worth performing further analysis.
(FSA - Sciences de l'ingénieur) – UCL, 2019
Advisors/Committee Members: UCL - SST/IMCN/MODL - Modelling, UCL - Ecole Polytechnique de Louvain, Rignanese, Gian-Marco, Wirtz, Ludger, Tkatchenko, Alexandre, Gonze, Xavier, Botti, Silvana, Gopalan, Venkatraman.
Subjects/Keywords: Nonlinear optics; High-throughput; First-principles; Semiconductors; Second Harmonic Generation (SHG)
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APA (6th Edition):
Naccarato, F. (2019). First-principles high-throughput study of linear and nonlinear optical materials. (Thesis). Université Catholique de Louvain. Retrieved from http://hdl.handle.net/2078.1/222564
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Naccarato, Francesco. “First-principles high-throughput study of linear and nonlinear optical materials.” 2019. Thesis, Université Catholique de Louvain. Accessed April 16, 2021.
http://hdl.handle.net/2078.1/222564.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Naccarato, Francesco. “First-principles high-throughput study of linear and nonlinear optical materials.” 2019. Web. 16 Apr 2021.
Vancouver:
Naccarato F. First-principles high-throughput study of linear and nonlinear optical materials. [Internet] [Thesis]. Université Catholique de Louvain; 2019. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/2078.1/222564.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Naccarato F. First-principles high-throughput study of linear and nonlinear optical materials. [Thesis]. Université Catholique de Louvain; 2019. Available from: http://hdl.handle.net/2078.1/222564
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of New Mexico
14.
Gragossian, Aram.
Synchronous generation and coherent control of extreme wavelength radiation and ultrafast spectroscopy.
Degree: Optical Science and Engineering, 2017, University of New Mexico
URL: https://digitalrepository.unm.edu/ose_etds/61
► Recent progress in ultrafast laser science has made it possible to synthesize and control complex electromagnetic waveforms down to sub-femtosecond timescales. These tailored ultrashort…
(more)
▼ Recent progress in ultrafast laser science has made it possible to synthesize and control complex electromagnetic waveforms down to sub-femtosecond timescales. These tailored ultrashort laser pulses can generate coherent bursts of electromagnetic radiation in the extreme ultraviolet (XUV) and terahertz spectral regions with durations reaching the attosecond regime in the XUV region. This is accomplished by coherently controlling electronic motion in gas plasma targets. With these novel radiation sources, ultrafast time-resolved spectroscopy can be performed on a large variety of materials. Knowledge of the spectral phase of an ultrashort pulse is crucial for many applications. There are a variety of ways to fully characterize the electric field but usually, involve an elaborate setup. It is highly desirable to have a method of pulse characterization without such complications. In this work, we introduce an algorithm that retrieves the electric field from the measured fundamental and two nonlinear spectra using an iterative process. This measurement technique is insensitive to optical alignment and imperfections of the beam spatial profile. The control of electronic motion enables the
generation of a wide range of coherent electromagnetic radiation. In this dissertation, we have combined the fundamental laser beam with its second
harmonic to simultaneously generate extreme ultraviolet (XUV) and terahertz radiation. Synchronous pulses in widely separated spectral regions opens the possibility of powerful time-resolved spectroscopy. We introduce an intuitive semi-classical model based on the well-known three-step description to explain the observed XUV and terahertz correlations. The transparency of this model provides an intuitive physical understanding of the complex features observed in the measured XUV spectra. Key insights are obtained from this model by identifying the effect of second
harmonic generation efficiency and the interference of short and long electron trajectories. Ultrashort bursts of electromagnetic radiation are powerful tools for time-resolved spectroscopy. Availability of short pulse durations over a broad spectral range aids the investigation of electron transport in a large variety of materials. We have utilized ultraviolet and XUV ultrashort pulses to probe electron transport in several inorganic scintillators. Scintillators are important because they absorb
high energy photons and convert this energy to visible luminescence. Excitation and conversion to visible fluorescence takes place on a timescale of tens of picoseconds. Ultrashort bursts of XUV are an ideal excitation source for these studies. The conversion to visible fluorescence is not 100% efficient as there are competing relaxation processes that can be identified from rise and decay time of the luminescence. The results from such measurements can provide guidance in the engineering of more efficient scintillators for
high energy radiation detection.
Advisors/Committee Members: Mansoor Sheik-Bahae, Jean-Claude Diels, Mani Hossein-Zadeh, Markus Hehlen.
Subjects/Keywords: Ultrafast; Ultrashort; Time-resolved spectroscopy; High harmonic generation; Terahertz generation; Optics; Other Engineering
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Export
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APA (6th Edition):
Gragossian, A. (2017). Synchronous generation and coherent control of extreme wavelength radiation and ultrafast spectroscopy. (Doctoral Dissertation). University of New Mexico. Retrieved from https://digitalrepository.unm.edu/ose_etds/61
Chicago Manual of Style (16th Edition):
Gragossian, Aram. “Synchronous generation and coherent control of extreme wavelength radiation and ultrafast spectroscopy.” 2017. Doctoral Dissertation, University of New Mexico. Accessed April 16, 2021.
https://digitalrepository.unm.edu/ose_etds/61.
MLA Handbook (7th Edition):
Gragossian, Aram. “Synchronous generation and coherent control of extreme wavelength radiation and ultrafast spectroscopy.” 2017. Web. 16 Apr 2021.
Vancouver:
Gragossian A. Synchronous generation and coherent control of extreme wavelength radiation and ultrafast spectroscopy. [Internet] [Doctoral dissertation]. University of New Mexico; 2017. [cited 2021 Apr 16].
Available from: https://digitalrepository.unm.edu/ose_etds/61.
Council of Science Editors:
Gragossian A. Synchronous generation and coherent control of extreme wavelength radiation and ultrafast spectroscopy. [Doctoral Dissertation]. University of New Mexico; 2017. Available from: https://digitalrepository.unm.edu/ose_etds/61
University of California – Berkeley
15.
Jager, Marieke Faye.
Attosecond Transient Absorption of Solid-State and Phase-Change Materials.
Degree: Chemical Engineering, 2017, University of California – Berkeley
URL: http://www.escholarship.org/uc/item/34x5t9rv
► Attosecond science, utilizing short bursts of extreme ultraviolet light, has opened up a fascinating new field of ultafast light-matter interactions, where dynamics in atomic, molecular,…
(more)
▼ Attosecond science, utilizing short bursts of extreme ultraviolet light, has opened up a fascinating new field of ultafast light-matter interactions, where dynamics in atomic, molecular, and solid state systems can now be followed on the timescale of electron motion. In this dissertation, applications of attosecond pulses toward performing transient absorption spectroscopy experiments on complex electron-correlation-driven processes in material systems are described. In the first chapter, a brief overview of ultrafast spectroscopy, attosecond pulse production, and light-matter interaction in the extreme ultraviolet is provided, which offers the necessary breadth and background for the detailed case study that follows, on the insulator-to-metal phase transition in vanadium dioxide.The origin of the bandgap in vanadium dioxide, which is not predicted to exist under conventional single-particle band theories, has been explained as the result of either electron correlation or structural distortion. The goal of the experiments presented herein is to use transient absorption spectroscopy with attosecond pulses to characterize the timescale of this process and gain a mechanistic understanding of how it occurs. Because vanadium dioxide is heat sensitive, an apparatus had to be specifically tailored to this type of experiments, and it is described in the second chapter. The results and analysis, including extreme ultraviolet static and time-resolved measurements on both the insulating and metallic phases, are described in the third chapter.The second half of this dissertation describes the design and construction of a new vacuum endstation to perform attosecond-pump attosecond-probe measurements, which was constructed and tested at Berkeley and installed at a high power attosecond beamline at the University of Central Florida. Ray tracing simulation and design considerations for the optical layout are described in the fourth chapter, and design of the vacuum endstation, diagnostics, and preliminary experiments and testing can be found in the fifth chapter.
Subjects/Keywords: Physical chemistry; Attosecond; High harmonic generation; Insulation to metal transition; Vanadium dioxide
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Manager
APA (6th Edition):
Jager, M. F. (2017). Attosecond Transient Absorption of Solid-State and Phase-Change Materials. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/34x5t9rv
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Jager, Marieke Faye. “Attosecond Transient Absorption of Solid-State and Phase-Change Materials.” 2017. Thesis, University of California – Berkeley. Accessed April 16, 2021.
http://www.escholarship.org/uc/item/34x5t9rv.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Jager, Marieke Faye. “Attosecond Transient Absorption of Solid-State and Phase-Change Materials.” 2017. Web. 16 Apr 2021.
Vancouver:
Jager MF. Attosecond Transient Absorption of Solid-State and Phase-Change Materials. [Internet] [Thesis]. University of California – Berkeley; 2017. [cited 2021 Apr 16].
Available from: http://www.escholarship.org/uc/item/34x5t9rv.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Jager MF. Attosecond Transient Absorption of Solid-State and Phase-Change Materials. [Thesis]. University of California – Berkeley; 2017. Available from: http://www.escholarship.org/uc/item/34x5t9rv
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of California – Berkeley
16.
Shaw, Brian Henry.
Laser-plasma interactions from thin tapes for high-energy electron accelerators and seeding compact FELs.
Degree: Applied Science & Technology, 2015, University of California – Berkeley
URL: http://www.escholarship.org/uc/item/9dm7h3jx
► For over 10 years, laser plasma acceleration (LPA) has been a rapidly growing technologyused to create electron beams on length-scales much smaller than that of…
(more)
▼ For over 10 years, laser plasma acceleration (LPA) has been a rapidly growing technologyused to create electron beams on length-scales much smaller than that of a conventionalRF-accelerator [1]. As electron beam properties improve, research for LPAs is expanding totake advantage of the creation and accessibility of high-quality electron beams from plasmatargets. Two applications which are currently being explored are a multi-stage plasmaaccelerator to reach energies greater than those a single-stage accelerator can achieve andexploring the possibility of an LPA based free-electron laser (FEL) light source. Researchsupporting both of these efforts has been performed on the 50 TW TREX laser system atthe BELLA Center at the Lawrence Berkeley National Lab, and the results of these effortsare described in this dissertation.Using chirped-pulsed amplification to produce high-quality laser pulses up to petawattlevels, experimental results have yielded laser driven electron beam energies up to 4.25GeV [2]. By tuning the density of the target, the accelerating gradients sustained by theplasma can grow beyond 100 GeV/m [3] (103 times larger than that of a conventional RFaccelerator). However, limiting factors such as dephasing of the electron beam from theplasma wake, defocusing of a laser pulse, and energy depletion of the laser into the plasmalimit the maximum sensible length of a plasma accelerator. Staging the LPA with two ormore accelerating modules could be the next step towards producing beams with energiesgreater than those possible with a single stage.One requirement for staged acceleration is that the laser pulse used to drive the firstaccelerating stage must be coupled out of the beamline, and a fresh laser pulse must becoupled in for the second stage to post accelerate the electrons. To do this while maintaininga short scale length between the two stages requires an optic to be placed near the final focus of the second laser pulse. Because damage will occur when the laser pulse interacts with a steering optic near focus, the coupling optic must be capable of replacing the surfacefollowing damage on each successive shot. This thesis comprises a detailed investigation of the physics of using a plasma mirror (PM) from a tape by reflecting ultrashort pulses froma laser-triggered surface plasma. The tapes used in the characterization of the PM are VHSand computer data storage tape. The tapes are 6.6 m (computer storage tape) and 15 m(VHS) thick. Each tape is 0.5 inches wide, and 10s of meters of tape are spooled using a tape drive; providing thousands of shots on a single reel of tape. The amount of reflected energy of the PM was studied for different input intensities. The fluence was varied by translating the focus of the laser upstream and downstream of the tape, which changed the spot size on the tape surface and hence changed the fluence. This study measured reflectances from both sides of the two tapes, and for input light of both s and p-polarizations. Lastly, an analytic model was developed to understand the…
Subjects/Keywords: Physics; Optics; Free-Electron Lasers; High-Harmonic Generation; Laser-Plasma Accelerators; Laser-Plasma Interactions
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APA (6th Edition):
Shaw, B. H. (2015). Laser-plasma interactions from thin tapes for high-energy electron accelerators and seeding compact FELs. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/9dm7h3jx
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Shaw, Brian Henry. “Laser-plasma interactions from thin tapes for high-energy electron accelerators and seeding compact FELs.” 2015. Thesis, University of California – Berkeley. Accessed April 16, 2021.
http://www.escholarship.org/uc/item/9dm7h3jx.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Shaw, Brian Henry. “Laser-plasma interactions from thin tapes for high-energy electron accelerators and seeding compact FELs.” 2015. Web. 16 Apr 2021.
Vancouver:
Shaw BH. Laser-plasma interactions from thin tapes for high-energy electron accelerators and seeding compact FELs. [Internet] [Thesis]. University of California – Berkeley; 2015. [cited 2021 Apr 16].
Available from: http://www.escholarship.org/uc/item/9dm7h3jx.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Shaw BH. Laser-plasma interactions from thin tapes for high-energy electron accelerators and seeding compact FELs. [Thesis]. University of California – Berkeley; 2015. Available from: http://www.escholarship.org/uc/item/9dm7h3jx
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of California – Berkeley
17.
Koh, Christine Jungmin.
Photodissociation and Hypergolic Reaction Dynamics of Ionic Liquids.
Degree: Chemistry, 2012, University of California – Berkeley
URL: http://www.escholarship.org/uc/item/4t98c9sb
► Ionic liquids (ILs) are room temperature molten salts with unique properties and broad range of applications. The properties are tunable based on the cation-anion (C+-A-)…
(more)
▼ Ionic liquids (ILs) are room temperature molten salts with unique properties and broad range of applications. The properties are tunable based on the cation-anion (C+-A-) combination. Studying the ion pairs provides understanding of the interaction between the isolated cation and anion, which primarily determines the electronic and nuclear structure. New velocity map imaging experiments were initiated to study the dissociative pathways upon photoexcitation of isolated ion pairs. Dissociative ionization and ion pair dissociation pathways initiated by 54 nm light of an IL, 1-ethy-3-methylimidazolium ([Emim]+) bis(trifluoromethyl-sulfonyl)imide ([Tf2N]-), are revealed. Furthermore, the ultrafast excited dynamics of an IL, [Emim]+[Br]-, has been studied using time-resolved photoion spectroscopy. Momentary depletion of the intact cation and rise of the alkyl-loss fragments are observed, suggesting a possibility for a short-lived electronically or internally excited state that promotes the formation of alkyl-loss fragments upon probe excitation. The volatilization process of thermally stable and unstable ionic liquids is studied using tunable vacuum ultraviolet light (VUV). Heats of vaporization for imidazolium-based ionic liquids are measured and the ionization threshold for the neutral ion pair is directly measured for the first time. The thermal decomposition mechanism for [Emim]+[Br]-is explored to understand the volatilization process better, showing that alkyl abstraction upon heating occurs via an SN2 type mechanism.Moreover, an IL hypergolic reaction mechanism is studied using an aerosol flow tube method combined with tunable VUV light to understand the reaction chemistry of a potentially less corrosive and toxic rocket fuel system. Isolated ion pairs are monitored from IL aerosols with the advantage of less photofragmentation. Observation of early stage reaction intermediates, cyanamide, N2O, and CO2 from a hypergolic IL reaction with nitric acid reveals the existence of a nitro-substituted intermediate.
Subjects/Keywords: Chemistry; Physical chemistry; extreme ultraviolet; high harmonic generation; hypergolic reaction; ionic liquid; ultrafast dynamcis
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APA (6th Edition):
Koh, C. J. (2012). Photodissociation and Hypergolic Reaction Dynamics of Ionic Liquids. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/4t98c9sb
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Koh, Christine Jungmin. “Photodissociation and Hypergolic Reaction Dynamics of Ionic Liquids.” 2012. Thesis, University of California – Berkeley. Accessed April 16, 2021.
http://www.escholarship.org/uc/item/4t98c9sb.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Koh, Christine Jungmin. “Photodissociation and Hypergolic Reaction Dynamics of Ionic Liquids.” 2012. Web. 16 Apr 2021.
Vancouver:
Koh CJ. Photodissociation and Hypergolic Reaction Dynamics of Ionic Liquids. [Internet] [Thesis]. University of California – Berkeley; 2012. [cited 2021 Apr 16].
Available from: http://www.escholarship.org/uc/item/4t98c9sb.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Koh CJ. Photodissociation and Hypergolic Reaction Dynamics of Ionic Liquids. [Thesis]. University of California – Berkeley; 2012. Available from: http://www.escholarship.org/uc/item/4t98c9sb
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Ottawa
18.
Alharbi, Abdullah F.
High-order Harmonic Spectroscopy of Cyclic Organic Molecules
.
Degree: 2016, University of Ottawa
URL: http://hdl.handle.net/10393/35179
► Understanding the electronic structure and dynamics of cyclic organic molecules is becoming increasingly the subject of investigations from different perspectives due to their unique chemical…
(more)
▼ Understanding the electronic structure and dynamics of cyclic organic molecules is becoming increasingly the subject of investigations from different perspectives due to their unique chemical and physical properties. Since they are largely involved in the biochemistry of living organisms, studies on this class of compounds are also valuable to understand biologically relevant complex systems. Compared to other techniques, high-order harmonic generation (HHG) has been increasingly considered as a powerful spectroscopic tool with Angstrom spatial and attosecond temporal resolutions. This thesis demonstrates that high-order harmonic spectroscopy is capable of providing structural and dynamical information on the electronic systems of representative cyclic organic molecules comprising randomly oriented five-membered or six-membered rings.
The first part of this thesis shows that the HHG from these molecules is sensitive to their aromatic character, which results from the de-localized pi electrons, and can potentially be a useful qualitative measure of aromaticity. We show that the advantage of utilizing HHG in this direction stems from the result that only pi molecular orbitals, associated with aromatcity, are responsible for the HHG emission in aromatic systems.
The capability of HHG to distinguish cyclic isomers is demonstrated in the case of xylene molecules. Supported by numerical calculations, differences in the isomers are attributed to both tunnel ionization and photorecombination, the first and last steps of HHG. These results enable further HHG-based time-resolved studies of the dynamics associated with isomeric effects that these molecules exhibit.
The present work also challenges the well-established prediction that strong field ionization from a molecular orbital is suppressed along nodal planes, where the electron density is zero. In fact, our study shows that considerable tunnel ionization in some cyclic molecules can occur near or along nodal planes. This unusual ionization is reported to have its signature on the quantitative and qualitative dependence of harmonic yield on laser ellipticity.
The high symmetry displayed by the cyclic molecule, 1,4 cyclohexadiene, is shown to leave its imprints on the HHG in the form of structural interferences even if the target is randomly oriented. Two-color HHG from this molecule also indicates that hole dynamics could be involved in the generation process.
A general study on high harmonic spectroscopy of the Cooper minimum in molecules is also reported. The presence of this minimum could affect the interpretation of harmonics spectra in any molecule containing S or Cl atoms. The molecular environment is shown to influence the position of this spectral modulation.
Subjects/Keywords: High-order harmonic generation;
Strong-field laser physics;
Cyclic organic molecules;
Molecular dynamics and structure
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Alharbi, A. F. (2016). High-order Harmonic Spectroscopy of Cyclic Organic Molecules
. (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/35179
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Alharbi, Abdullah F. “High-order Harmonic Spectroscopy of Cyclic Organic Molecules
.” 2016. Thesis, University of Ottawa. Accessed April 16, 2021.
http://hdl.handle.net/10393/35179.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Alharbi, Abdullah F. “High-order Harmonic Spectroscopy of Cyclic Organic Molecules
.” 2016. Web. 16 Apr 2021.
Vancouver:
Alharbi AF. High-order Harmonic Spectroscopy of Cyclic Organic Molecules
. [Internet] [Thesis]. University of Ottawa; 2016. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/10393/35179.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Alharbi AF. High-order Harmonic Spectroscopy of Cyclic Organic Molecules
. [Thesis]. University of Ottawa; 2016. Available from: http://hdl.handle.net/10393/35179
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Ottawa
19.
Kong, Fanqi.
High-Order Harmonic Generation with Structured Beams
.
Degree: 2019, University of Ottawa
URL: http://hdl.handle.net/10393/39609
► The generation of high-order harmonics opened an era of attosecond science wherein coherent light bursts are used to probe dynamic processes in matter with a…
(more)
▼ The generation of high-order harmonics opened an era of attosecond science wherein coherent light bursts are used to probe dynamic processes in matter with a time resolution short enough to resolve the motions of electrons. It enabled the development of extreme ultraviolet (XUV) and X-ray table-top sources with both temporal and spatial coherence, which provides the ability to shape the temporal and spatial structure of the XUV pulses.
Scientists developed techniques to control and measure the temporal structure high harmonic emissions. These techniques exploited control of the driving laser pulse in the time domain and facilitated development of more advanced high-harmonic based XUV sources that have greatly impacted ultrafast measurements.
In this thesis, I apply techniques to control and measure the spatial structure of high harmonic emissions, and discuss the underlying physics and potential applications of the interaction between spatially structured laser beams and materials. This study exploits the spatial degree of freedom in strong field interaction, which has not been given as much attention as the temporal degree of freedom.
I use liquid crystal devices to shape the wave front of a fundamental laser beam to a vortex structure, then imprint this structured wave front onto XUV beams through high harmonic generation. This method provides an alternative to special XUV optics, which can manipulate the wave front of XUV radiation by all optical means. This result also reveals the conservation of orbital angular momentum in this extreme nonlinear wave mixing process. In addition to shaping the wave front, shaping the polarization of the driving beam also allows generation of circularly polarized the XUV radiation using a high harmonic source.
This thesis also highlights the interplay between shaping the wave front and polarization in the high harmonic generation process. The topology of the structured beam can be maintained through this extreme nonlinear interaction due to the spin selection rules and spin-orbit conservation.
Moreover, this thesis demonstrates an approach to integrate a vector beam into a broadband ultrafast light source and overcome the bandwidth limitation of mode converters. We use this approach to generate a few-cycle structured beam. In the future, this beam will be used to generate a strong ultrafast magnetic impulse in gas and solid targets by driving currents in a loop, which is a valuable tool for the future of magnetic metrology.
The novel properties of structured laser beams discussed in this thesis expanded the capabilities of high harmonic based XUV sources and have opened a new field to explore this additional degree of freedom in strong field interactions.
Subjects/Keywords: High Harmonic Generation;
Optics;
Strong Field Physics;
Extreme Ultraviolet;
Beam Shaping;
Structured Beam
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kong, F. (2019). High-Order Harmonic Generation with Structured Beams
. (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/39609
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Kong, Fanqi. “High-Order Harmonic Generation with Structured Beams
.” 2019. Thesis, University of Ottawa. Accessed April 16, 2021.
http://hdl.handle.net/10393/39609.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Kong, Fanqi. “High-Order Harmonic Generation with Structured Beams
.” 2019. Web. 16 Apr 2021.
Vancouver:
Kong F. High-Order Harmonic Generation with Structured Beams
. [Internet] [Thesis]. University of Ottawa; 2019. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/10393/39609.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Kong F. High-Order Harmonic Generation with Structured Beams
. [Thesis]. University of Ottawa; 2019. Available from: http://hdl.handle.net/10393/39609
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Colorado
20.
Chen, Cong.
Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy.
Degree: PhD, 2018, University of Colorado
URL: https://scholar.colorado.edu/phys_gradetds/260
► Recent advances in the generation and control of attosecond light pulses have opened up new opportunities for the real-time observation of sub-femtosecond (1 fs =…
(more)
▼ Recent advances in the
generation and control of attosecond light pulses have opened up new opportunities for the real-time observation of sub-femtosecond (1 fs = 10
-15 s) electron dynamics in gases and solids. Combining attosecond light pulses with angle-resolved photoelectron spectroscopy (atto-ARPES) provides a powerful new technique to study the influence of material band structure on attosecond electron dynamics in materials. Electron dynamics that are only now accessible include the lifetime of far-above-bandgap excited electronic states, as well as fundamental electron interactions such as scattering and screening. In addition, the same atto-ARPES technique can also be used to measure the temporal structure of complex coherent light fields. In this thesis, I present four experiments utilizing atto-ARPES to provide new insights into the
generation and characterization of attosecond light pulses, as well as the attosecond electron dynamics in transition metals. First, I describe a new method to extend attosecond metrology techniques to the reconstruction of circularly polarized attosecond light pulses for the first time. Second, I show that by driving
high harmonics with a two-color linearly polarized laser field, quasi-isolated attosecond pulses are generated because the phase matching window is confined. Third, I present the first measurement of lifetimes for photoelectrons that are born into free-electron-like states compared with those that are excited into unoccupied excited states in the band structure of a material (Ni(111)). The finite excited-state lifetime causes a ≈200 as delay in the emission of photoelectrons. Finally, I describe direct time-domain studies of electron-electron interactions in transition metals with both simple and complex Fermi surfaces. In particular, I show the influence of electron-electron scattering and screening on the lifetime of photoelectrons.
Advisors/Committee Members: Margaret M. Murnane, Henry C. Kapteyn, Andreas Becker.
Subjects/Keywords: attosecond; electron dynamics; euv; high harmonic generation; photoemission; ultrafast; Dynamical Systems; Physics
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APA ·
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MLA ·
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CSE |
Export
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APA (6th Edition):
Chen, C. (2018). Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/phys_gradetds/260
Chicago Manual of Style (16th Edition):
Chen, Cong. “Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy.” 2018. Doctoral Dissertation, University of Colorado. Accessed April 16, 2021.
https://scholar.colorado.edu/phys_gradetds/260.
MLA Handbook (7th Edition):
Chen, Cong. “Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy.” 2018. Web. 16 Apr 2021.
Vancouver:
Chen C. Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy. [Internet] [Doctoral dissertation]. University of Colorado; 2018. [cited 2021 Apr 16].
Available from: https://scholar.colorado.edu/phys_gradetds/260.
Council of Science Editors:
Chen C. Attosecond Light Pulses and Attosecond Electron Dynamics Probed Using Angle-Resolved Photoelectron Spectroscopy. [Doctoral Dissertation]. University of Colorado; 2018. Available from: https://scholar.colorado.edu/phys_gradetds/260
University of Colorado
21.
Tengdin, Phoebe Marie.
Direct Optically Driven Spin-Charge Dynamics Govern the Femtosecond Response of Ferromagnets.
Degree: PhD, 2019, University of Colorado
URL: https://scholar.colorado.edu/eeng_gradetds/35
► Ferromagnetic materials have strong electron correlations that drive quantum effects and make the physics that describes them extremely challenging. In particular, the electron, spin, and…
(more)
▼ Ferromagnetic materials have strong electron correlations that drive quantum effects and make the physics that describes them extremely challenging. In particular, the electron, spin, and lattice degrees of freedom can interact in surprising ways when driven out of equilibrium by ultrafast laser excitation. In this thesis I uncover several previously unexpected connections between the electronic and spin systems in ferromagnets. Dynamics occur at unexpectedly fast timescales, driven using femtosecond laser excitation pulses. The tools that I use to observe the exceeding fast (10s of femtosecond) dynamics are bursts of extreme ultraviolet light resonant with the M-edge of transition metals and produced via
high harmonic generation. We combine time-resolved transverse magneto-optical Kerr effect and time- and angle-resolved photoemission spectroscopies to show that the same critical behavior that governs the equilibrium magnetic phase transition in nickel also governs the ultrafast dynamics within 20 fs of laser excitation. When the electron temperature is transiently driven above the Curie temperature, we observe an extremely rapid change in the material response: the spin system absorbs sufficient energy within the first 20 fs to subsequently proceed through the phase transition, whereas demagnetization and the collapse of the exchange splitting occur on much longer, fluence- independent time scales of 176 fs. This observation defines a new timescale in the field of ultrafast ferromagnetism. The next question is then whether or not a response at this speed or faster can be directly observed in more complex materials. To investigate this I perform experiments on the half-metallic heusler compound Co
2MnGe. Here a single infrared femtosecond laser pulse drives ultrafast transfer of spin polarization from one elemental sublattice to another within its pulse duration. I simultaneously probe the magnetic response of cobalt and manganese to make a surprising finding: the magnetization of Co is transiently enhanced, while that of Mn rapidly quenches. This marks the first direct manipulation of electron spins via light, providing a path to spintronic logic devices such as switches and triggers that operate on few femtosecond or even faster timescales.
Advisors/Committee Members: Margaret M. Murnane, Henry Kapteyn, Tom J. Silva, Hans Nembach, Xiaobo Yin.
Subjects/Keywords: correlated electrons; ferromagnetism; high harmonic generation; quantum materials; ultrafast; Materials Science and Engineering; Optics
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APA (6th Edition):
Tengdin, P. M. (2019). Direct Optically Driven Spin-Charge Dynamics Govern the Femtosecond Response of Ferromagnets. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/eeng_gradetds/35
Chicago Manual of Style (16th Edition):
Tengdin, Phoebe Marie. “Direct Optically Driven Spin-Charge Dynamics Govern the Femtosecond Response of Ferromagnets.” 2019. Doctoral Dissertation, University of Colorado. Accessed April 16, 2021.
https://scholar.colorado.edu/eeng_gradetds/35.
MLA Handbook (7th Edition):
Tengdin, Phoebe Marie. “Direct Optically Driven Spin-Charge Dynamics Govern the Femtosecond Response of Ferromagnets.” 2019. Web. 16 Apr 2021.
Vancouver:
Tengdin PM. Direct Optically Driven Spin-Charge Dynamics Govern the Femtosecond Response of Ferromagnets. [Internet] [Doctoral dissertation]. University of Colorado; 2019. [cited 2021 Apr 16].
Available from: https://scholar.colorado.edu/eeng_gradetds/35.
Council of Science Editors:
Tengdin PM. Direct Optically Driven Spin-Charge Dynamics Govern the Femtosecond Response of Ferromagnets. [Doctoral Dissertation]. University of Colorado; 2019. Available from: https://scholar.colorado.edu/eeng_gradetds/35
University of Colorado
22.
Lock, Robynne Marie.
High Harmonic Generation from Rotationally Excited Molecules.
Degree: PhD, Physics, 2011, University of Colorado
URL: https://scholar.colorado.edu/phys_gradetds/29
► High harmonic generation (HHG) is understood through a three-step model. A strong laser field ionizes an atom or molecule. The free electron propagates in…
(more)
▼ High harmonic generation (HHG) is understood through a three-step model. A strong laser field ionizes an atom or molecule. The free electron propagates in the laser field and may recombine with the atom or molecule leading to the
generation of extreme ultraviolet or soft x-ray light at odd harmonics of the fundamental. Since the wavelength of the recombining electron is on the order of internuclear distances in molecules, HHG acts as a probe of molecular structure and dynamics. Conversely, control of the molecules leads to control of the properties (intensity, phase, and polarization) of the
harmonic emission. Rotationally exciting molecules provides field-free molecular alignment at time intervals corresponding to fractions of the rotational period of the molecule. Alignment is necessary for understanding how the
harmonic emission depends on molecular structure and alignment. Additionally, HHG acts as a probe of the rotational wavepackets. This thesis reports three experiments on HHG from rotationally excited molecules. Before we can use HHG as a probe of complex molecular dynamics or control
harmonic properties through molecules, the
harmonic emission from aligned, linear molecules must first be understood. To that end, the first experiment measures the intensity and phase of harmonics generated from N
2O and N
2 near times of strong alignment revealing interferences during recombination. The second experiment demonstrates HHG as a sensitive probe of rotational wavepacket dynamics in CO
2 and N
2O, revealing new revival features not detected by any other probe. The final experiment focuses on understanding and controlling the polarization state of the
harmonic emission. Generating elliptically polarized harmonics would be very useful for probing molecular and materials systems. We observe an elliptical dichroism in polarization-resolved measurements of the
harmonic emission from aligned N
2 and CO
2 molecules, revealing evidence for electron-hole dynamics between the times of ionization and recombination.
Advisors/Committee Members: Margaret M. Murnane, Henry C. Kapteyn, Andreas Becker.
Subjects/Keywords: high harmonic generation; strong field physics; ultrafast phenomena; Atomic, Molecular and Optical Physics
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Lock, R. M. (2011). High Harmonic Generation from Rotationally Excited Molecules. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/phys_gradetds/29
Chicago Manual of Style (16th Edition):
Lock, Robynne Marie. “High Harmonic Generation from Rotationally Excited Molecules.” 2011. Doctoral Dissertation, University of Colorado. Accessed April 16, 2021.
https://scholar.colorado.edu/phys_gradetds/29.
MLA Handbook (7th Edition):
Lock, Robynne Marie. “High Harmonic Generation from Rotationally Excited Molecules.” 2011. Web. 16 Apr 2021.
Vancouver:
Lock RM. High Harmonic Generation from Rotationally Excited Molecules. [Internet] [Doctoral dissertation]. University of Colorado; 2011. [cited 2021 Apr 16].
Available from: https://scholar.colorado.edu/phys_gradetds/29.
Council of Science Editors:
Lock RM. High Harmonic Generation from Rotationally Excited Molecules. [Doctoral Dissertation]. University of Colorado; 2011. Available from: https://scholar.colorado.edu/phys_gradetds/29
University of Colorado
23.
Li, Qing.
Study of Nanoscale Phonon Dynamics using Ultrafast Coherent Extreme Ultraviolet Beams.
Degree: PhD, Physics, 2011, University of Colorado
URL: https://scholar.colorado.edu/phys_gradetds/54
► Phonon transport is essential in both understanding and characterizing materials, particularly in nanoscale systems. In this thesis, I use coherent ultrafast extreme ultraviolet (EUV)…
(more)
▼ Phonon transport is essential in both understanding and characterizing materials, particularly in nanoscale systems. In this thesis, I use coherent ultrafast extreme ultraviolet (EUV) beams from
high-order
harmonic generation, to study the dynamics of photoacoustics and energy-carrying phonons at the nanoscale. I first generate and detect short-wavelength photoacoustic waves by impulsively heating sub-optical phononic crystals with an infrared laser. By monitoring the diffraction dynamics of EUV beams I observe the shortest-wavelength surface acoustic waves to date at 35 nm, corresponding to an interface layer sensitivity of sub-10 nm. I also achieve coherent control of SAW
generation and preferentially enhance higher-order SAWs which allows us to reduce the generated SAW wavelength by a factor of two for a defined nanostructure period. I apply this photoacoustic technique to thin film metrology metrology: by generating nanoscale longitudinal and surface acoustic waves simultaneously, I am able to characterize the mechanical properties of ultrathin film samples. Secondly, I study thermal transport dynamics in nano-to-bulk systems where phonons are heat carriers. I first observed quasi-ballistic thermal transport in 1D nano-to-bulk systems, and detect a stronger ballistic effect in 2D nanostructured materials. Temperature- and polarization-dependent experiments are also reported in this thesis. Furthermore, I was able to make a first attempt in dynamic thermal imaging using coherent diffraction of EUV beams.
Advisors/Committee Members: Margaret M. Murnane, Henry C. Kapteyn, Ronggui Yang.
Subjects/Keywords: ballistic effect; extreme ultraviolet; high harmonic generation; photoacoustic; surface acoustic wave; thermal transport; Physics
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APA (6th Edition):
Li, Q. (2011). Study of Nanoscale Phonon Dynamics using Ultrafast Coherent Extreme Ultraviolet Beams. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/phys_gradetds/54
Chicago Manual of Style (16th Edition):
Li, Qing. “Study of Nanoscale Phonon Dynamics using Ultrafast Coherent Extreme Ultraviolet Beams.” 2011. Doctoral Dissertation, University of Colorado. Accessed April 16, 2021.
https://scholar.colorado.edu/phys_gradetds/54.
MLA Handbook (7th Edition):
Li, Qing. “Study of Nanoscale Phonon Dynamics using Ultrafast Coherent Extreme Ultraviolet Beams.” 2011. Web. 16 Apr 2021.
Vancouver:
Li Q. Study of Nanoscale Phonon Dynamics using Ultrafast Coherent Extreme Ultraviolet Beams. [Internet] [Doctoral dissertation]. University of Colorado; 2011. [cited 2021 Apr 16].
Available from: https://scholar.colorado.edu/phys_gradetds/54.
Council of Science Editors:
Li Q. Study of Nanoscale Phonon Dynamics using Ultrafast Coherent Extreme Ultraviolet Beams. [Doctoral Dissertation]. University of Colorado; 2011. Available from: https://scholar.colorado.edu/phys_gradetds/54
24.
Gruson, Vincent.
Polarimétrie harmonique et spectroscopie de photoionisation attoseconde : Harmonic polarimetry and attosecond photoionization spectroscopy.
Degree: Docteur es, Lasers, molécules, rayonnement atmosphérique, 2015, Université Paris-Saclay (ComUE)
URL: http://www.theses.fr/2015SACLS227
► La physique attoseconde est un domaine en pleine expansion, intrinsèquement lié au processus de génération d’harmoniques d’ordre élevé. Cette émission, sous forme d’un train d’impulsions…
(more)
▼ La physique attoseconde est un domaine en pleine expansion, intrinsèquement lié au processus de génération d’harmoniques d’ordre élevé. Cette émission, sous forme d’un train d’impulsions attosecondes ou d’une impulsion attoseconde isolée, constitue une source de lumière dans le domaine spectral extrême-UV (XUV), ultra-brève, cohérente, parfaitement synchrone du champ générateur. Deux thématiques ont été abordées. La première consiste en la caractérisation complète de l’état de polarisation des harmoniques par Polarimétrie Moléculaire en collaboration avec l’ISMO-Orsay. Cette technique est basée sur la mesure de la distribution angulaire des photoélectrons dans le référentiel moléculaire lors de l’ionisation dissociative de la molécule de NO. Nous l’appliquons à trois configurations produisant un rayonnement harmonique polarisé elliptiquement. Nous obtenons ainsi, pour la première fois, la valeur absolue de l’ellipticité harmonique, son signe, ainsi que le taux de dépolarisation.La seconde thématique est la photoionisation attoseconde résonante : nous avons étudié la photoionisation de l’hélium au voisinage de la résonance d'autoionisation 2s2p à 60.15eV, excitée par une impulsion XUV accordable et sondée par une impulsion laser IR en utilisant la technique RABBIT, qui permet la mesure de l’amplitude et de la phase spectrales de la transition résonante à deux photons. Il est ainsi possible de reconstruire dans le domaine temporel, le paquet d'ondes électronique (POE) à 2 photons. Ces mesures ont été complétées par des simulations effectuées par nos collaborateurs à UAM-Madrid et au LCPMR-Paris, qui montrent que, dans nos conditions expérimentales, ce paquet à deux photons est une image fidèle du paquet résonant à un photon. Ceci représente la première reconstruction de la dynamique temporelle d’une résonance non perturbée par le champ laser, avec une résolution attoseconde.
Attosecond physics is an expending field, intrinsically linked to the High Harmonic Generation process. This emission, which can be either an attosecond pulse train or an isolated attosecond pulse, constitutes a light source in the extreme-UV (XUV) spectral domain, coherent, perfectly synchronous of the generating field. Two thematic have been studied. The first one consists in the complete characterization of the harmonic emission through Molecular Polarimetry, in collaboration with ISMO-Orsay. This technique is based on the measurement of the Molecular Frame PhotoElectron Angular Distribution, during the dissociative ionization of NO molecules. We applied this technique to three configurations producing an elliptically polarized light. For the first time, we obtain the absolute value of the ellipticity, its sign and the depolarization rate. The second topic is the resonant attosecond photoionization: we studied the photoionization of helium, close to the 2s2p autoionization resonance at 60.15 eV, excited by a tunable XUV pulse and probed by an IR pulse, using RABBIT technique, enabling the measurement of the spectral amplitude and phase of the…
Advisors/Committee Members: Salières, Pascal (thesis director).
Subjects/Keywords: Génération d'harmoniques d'ordre élevé; Attoseconde; Polarimétrie; Rabbit; High Harmonic Generation; Attosecond; Polarimetry; Rabbit
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APA (6th Edition):
Gruson, V. (2015). Polarimétrie harmonique et spectroscopie de photoionisation attoseconde : Harmonic polarimetry and attosecond photoionization spectroscopy. (Doctoral Dissertation). Université Paris-Saclay (ComUE). Retrieved from http://www.theses.fr/2015SACLS227
Chicago Manual of Style (16th Edition):
Gruson, Vincent. “Polarimétrie harmonique et spectroscopie de photoionisation attoseconde : Harmonic polarimetry and attosecond photoionization spectroscopy.” 2015. Doctoral Dissertation, Université Paris-Saclay (ComUE). Accessed April 16, 2021.
http://www.theses.fr/2015SACLS227.
MLA Handbook (7th Edition):
Gruson, Vincent. “Polarimétrie harmonique et spectroscopie de photoionisation attoseconde : Harmonic polarimetry and attosecond photoionization spectroscopy.” 2015. Web. 16 Apr 2021.
Vancouver:
Gruson V. Polarimétrie harmonique et spectroscopie de photoionisation attoseconde : Harmonic polarimetry and attosecond photoionization spectroscopy. [Internet] [Doctoral dissertation]. Université Paris-Saclay (ComUE); 2015. [cited 2021 Apr 16].
Available from: http://www.theses.fr/2015SACLS227.
Council of Science Editors:
Gruson V. Polarimétrie harmonique et spectroscopie de photoionisation attoseconde : Harmonic polarimetry and attosecond photoionization spectroscopy. [Doctoral Dissertation]. Université Paris-Saclay (ComUE); 2015. Available from: http://www.theses.fr/2015SACLS227
University of Arizona
25.
Goodell, Brian Carpenter.
Probing Intracavity Plasma Dynamics with Higher-Order Transverse Modes
.
Degree: 2017, University of Arizona
URL: http://hdl.handle.net/10150/625686
► Extreme ultraviolet (XUV) frequency combs exhibit promise for enabling high-precision spectroscopic measurements of myriad chemical species for the first time. Coherent XUV radiation can be…
(more)
▼ Extreme ultraviolet (XUV) frequency combs exhibit promise for enabling
high-precision spectroscopic measurements of myriad chemical species for the first time. Coherent XUV radiation can be generated through
high harmonic generation (HHG) in femtosecond enhancement cavities. HHG efficiency is limited by nonlinear phase shifts induced by residual intracavity plasma. The goal of this work is to gain insight regarding plasma dynamics in order to allay the detrimental effects of plasma interactions. Our approach is to conduct simulations of cavity pump-probe experiments by probing with higher-order transverse modes. We propose methods for estimating spatial plasma profiles, gas jet velocities, and the plasma recombination coefficient based on measurements of plasma-induced phase shifts. Beam distortion due to plasma interaction is analyzed and used as another reference for plasma dynamics.
Advisors/Committee Members: Jones, Ronald J (advisor), Jones, Ronald J. (committeemember), Wright, Ewan M. (committeemember), Anderson, Brian P. (committeemember).
Subjects/Keywords: extreme ultraviolt;
frequency comb;
higher-order modes;
high harmonic generation;
intracavity plasma;
ultrafast
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APA (6th Edition):
Goodell, B. C. (2017). Probing Intracavity Plasma Dynamics with Higher-Order Transverse Modes
. (Masters Thesis). University of Arizona. Retrieved from http://hdl.handle.net/10150/625686
Chicago Manual of Style (16th Edition):
Goodell, Brian Carpenter. “Probing Intracavity Plasma Dynamics with Higher-Order Transverse Modes
.” 2017. Masters Thesis, University of Arizona. Accessed April 16, 2021.
http://hdl.handle.net/10150/625686.
MLA Handbook (7th Edition):
Goodell, Brian Carpenter. “Probing Intracavity Plasma Dynamics with Higher-Order Transverse Modes
.” 2017. Web. 16 Apr 2021.
Vancouver:
Goodell BC. Probing Intracavity Plasma Dynamics with Higher-Order Transverse Modes
. [Internet] [Masters thesis]. University of Arizona; 2017. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/10150/625686.
Council of Science Editors:
Goodell BC. Probing Intracavity Plasma Dynamics with Higher-Order Transverse Modes
. [Masters Thesis]. University of Arizona; 2017. Available from: http://hdl.handle.net/10150/625686
University of Arizona
26.
Timmers, Henry Robert.
Ultrafast XUV Spectroscopy: Unveiling the Nature of Electronic Couplings in Molecular Dynamics
.
Degree: 2014, University of Arizona
URL: http://hdl.handle.net/10150/338937
► Molecules are traditionally treated quantum mechanically using the Born-Oppenheimer formalism. In this formalism, different electronic states of the molecule are treated independently. However, most photo-initiated…
(more)
▼ Molecules are traditionally treated quantum mechanically using the Born-Oppenheimer formalism. In this formalism, different electronic states of the molecule are treated independently. However, most photo-initiated phenomena occurring in nature are driven by the couplings between different electronic states in both isolated molecules and molecular aggregates, and therefore occur beyond the Born-Oppenheimer formalism. These couplings are relevant in reactions relating to the perception of vision in the human eye, the oxidative damage and repair of DNA, the harvesting of light in photosynthesis, and the transfer of charge across large chains of molecules. While these reaction dynamics have traditionally been studied with visible and ultraviolet spectroscopy, attosecond XUV pulses formed through the process of
high harmonic generation form a perfect tool for probing coupled electronic dynamics in molecules. In this thesis, I will present our work in using ultrafast, XUV spectroscopy to study these dynamics in molecules of increasing complexity. We begin by probing the relaxation dynamics of superexcited states in diatomic O₂. These states can relax via two types of electronic couplings, either through autoionization or neutral dissociation. We find that our pump-probe scheme can disentangle the two relaxation mechanisms and independently measure their contributing lifetimes. Next, we present our work in observing a coherent electron hole wavepacket initiated by the ionization of polyatomic CO₂ near a conical intersection. The electron-nuclear couplings near the conical intersection drive the electron hole between different orbital configurations. We find that we can not only measure the lifetime of quantum coherence in the electron hole wavepacket, but also control its evolution with a strong, infrared probing field. Finally, we propose an experiment to observe the migration of an electron hole across iodobenzene on the few-femtosecond timescale. We present experimental modifications made to the
high harmonic generation set-up in order to probe this ultrafast and elusive charge migration. These results demonstrate the potential of ultrafast, XUV spectroscopy in probing the inner-workings of electronic couplings occurring in nature.
Advisors/Committee Members: Sandhu, Arvinder (advisor), Sandhu, Arvinder (committeemember), Cronin, Alex (committeemember), Huxter, Vanessa (committeemember), Wang, Weigang (committeemember).
Subjects/Keywords: Extreme Ultraviolet;
Femtosecond;
High Harmonic Generation;
Molecular Dynamics;
Non-adiabatic Dynamics;
Attosecond;
Physics
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Timmers, H. R. (2014). Ultrafast XUV Spectroscopy: Unveiling the Nature of Electronic Couplings in Molecular Dynamics
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/338937
Chicago Manual of Style (16th Edition):
Timmers, Henry Robert. “Ultrafast XUV Spectroscopy: Unveiling the Nature of Electronic Couplings in Molecular Dynamics
.” 2014. Doctoral Dissertation, University of Arizona. Accessed April 16, 2021.
http://hdl.handle.net/10150/338937.
MLA Handbook (7th Edition):
Timmers, Henry Robert. “Ultrafast XUV Spectroscopy: Unveiling the Nature of Electronic Couplings in Molecular Dynamics
.” 2014. Web. 16 Apr 2021.
Vancouver:
Timmers HR. Ultrafast XUV Spectroscopy: Unveiling the Nature of Electronic Couplings in Molecular Dynamics
. [Internet] [Doctoral dissertation]. University of Arizona; 2014. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/10150/338937.
Council of Science Editors:
Timmers HR. Ultrafast XUV Spectroscopy: Unveiling the Nature of Electronic Couplings in Molecular Dynamics
. [Doctoral Dissertation]. University of Arizona; 2014. Available from: http://hdl.handle.net/10150/338937
Louisiana State University
27.
Camp, Seth Jacob.
Resonant Interactions in Strong Field Laser Physics.
Degree: PhD, Physical Sciences and Mathematics, 2017, Louisiana State University
URL: etd-06232017-140117
;
https://digitalcommons.lsu.edu/gradschool_dissertations/4478
► We present a theoretical study of the influence of resonant enhancement on high harmonic generation for harmonics near the ionization threshold of helium and argon…
(more)
▼ We present a theoretical study of the influence of resonant enhancement on high harmonic generation for harmonics near the ionization threshold of helium and argon atoms. This is done by solving the time-dependent Schrodinger equation (TDSE) for the interaction between an atom and a driving laser pulse. By varying parameters of the driving laser pulse, we are able to identify the enhancement of harmonics resulting from multiphoton resonances between the ground state and Stark-shifted excited states of the atom. In this way, spectral and temporal signatures of resonant enhancement are identified and highlighted. We also study trajectory dynamics in HHG. For resonances occurring at the peak intensity of the driving laser pulse, we use time-frequency analysis on the emission to show that both long and short quantum path contributions to the harmonic yield can be enhanced. In this case, we also show that the phase of the long quantum path can be perturbed by the resonant interaction. For resonances occurring at intensities below the peak intensity, we demonstrate a new approach to studying resonant enhancement in both the time and spectral domain. This approach allows us to separate the long and short quantum path spectrally, allowing for unique insight into quantum path dynamics during the interaction with the strong laser field. We compare our results to those of recent experiments and find good agreement.
We also present a theoretical study of the interaction of extreme ultraviolet (XUV) pulses with a resonant macroscopic medium in transient absorption. In order to do this, the coupled TDSE and Maxwell's wave equation (MWE) are solved for an electric field propagating through a gas of atoms. We first show that a resonant medium can act to greatly alter the absorption line shape of an XUV pulse, when the medium is optically thick and the resonance is long-lived. This is demonstrated to be an effect of resonant pulse propagation, a temporal reshaping of light pulses interacting with long-lived resonances (relative to the duration of the pulse). The evolution of this spectral and temporal reshaping with increased propagation distance and gas pressure is investigated, both theoretically and experimentally. We next demonstrate a new optical tool that we have developed for controlling the spatial properties of XUV light. This optical tool uses an infrared pulse to tailor the emission direction of free-induction decay in a gas after a resonant XUV pulse excites the atoms. This technique is explored in both theory and experimental work, demonstrating the spatial control in two different geometries. It is also shown that this technique can be used to spectrally study the atomic response of atoms independently from the excitation pulse. This is a unique scenario, as typically the atomic response is measured as absorption in the spectrum of the excitation pulse.
Subjects/Keywords: high harmonic generation; transient absorption; ultrafast physics; strong field laser physics; macroscopic propagation; resonant interactions
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APA (6th Edition):
Camp, S. J. (2017). Resonant Interactions in Strong Field Laser Physics. (Doctoral Dissertation). Louisiana State University. Retrieved from etd-06232017-140117 ; https://digitalcommons.lsu.edu/gradschool_dissertations/4478
Chicago Manual of Style (16th Edition):
Camp, Seth Jacob. “Resonant Interactions in Strong Field Laser Physics.” 2017. Doctoral Dissertation, Louisiana State University. Accessed April 16, 2021.
etd-06232017-140117 ; https://digitalcommons.lsu.edu/gradschool_dissertations/4478.
MLA Handbook (7th Edition):
Camp, Seth Jacob. “Resonant Interactions in Strong Field Laser Physics.” 2017. Web. 16 Apr 2021.
Vancouver:
Camp SJ. Resonant Interactions in Strong Field Laser Physics. [Internet] [Doctoral dissertation]. Louisiana State University; 2017. [cited 2021 Apr 16].
Available from: etd-06232017-140117 ; https://digitalcommons.lsu.edu/gradschool_dissertations/4478.
Council of Science Editors:
Camp SJ. Resonant Interactions in Strong Field Laser Physics. [Doctoral Dissertation]. Louisiana State University; 2017. Available from: etd-06232017-140117 ; https://digitalcommons.lsu.edu/gradschool_dissertations/4478
28.
Cao, Wei.
Pump-probe
study of atoms and small molecules with laser driven high order
harmonics.
Degree: PhD, Department of
Physics, 2014, Kansas State University
URL: http://hdl.handle.net/2097/18161
► A commercially available modern laser can emit over 1015 photons within a time window of a few tens of femtoseconds (10-15 second), which can be…
(more)
▼ A commercially available modern laser can emit over
10
15 photons within a time window of a few tens of femtoseconds
(10
-15 second), which can be focused into a spot size of about 10
um, resulting in a peak intensity above 10
14 W/cm
2. This paves
the way for table-top strong field physics studies such as above
threshold ionization (ATI), non-sequential double ionization
(NSDI),
high order
harmonic generation (HHG), etc.. Among these
strong laser-matter interactions,
high order
harmonic generation,
which combines many photons of the fundamental laser field into a
single photon, offers a unique way to generate light sources in the
vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) region.
High
order
harmonic photons are emitted within a short time window from
a few tens of femtoseconds down to a few hundreds of attoseconds
(10
-18 second). This highly coherent nature of HHG allows it to be
synchronized with an infrared (IR) laser pulse, and the pump-probe
technique can be adopted to study ultrafast dynamic processes in a
quantum system. The major work of this thesis is to develop a
table-top VUV(EUV) light source based on HHG, and use it to study
dynamic processes in atoms and small molecules with the
VUV(EUV)-pump IR-probe method. A Cold Target Recoil Ion Momentum
Spectroscopy (COLTRIMS) apparatus is used for momentum imaging of
the interaction products. Two types of
high harmonic pump pulses
are generated and applied for pump-probe studies. The first one
consists of several harmonics forming a short attosecond pulse
train (APT) in the EUV regime (around 40 eV). We demonstrate that,
(1) the auto-ionization process triggered by the EUV in cation
carbon-monoxide and oxygen molecules can be modified by scanning
the EUV-IR delay, (2) the phase information of quantum trajectories
in bifurcated
high harmonics can be extracted by performing an
EUV-IR cross-correlation experiment, thus disclosing the
macroscopic quantum control in HHG. The second type of
high
harmonic source implemented in this work is a single
harmonic in
the VUV regime (around 15 eV) filtered out from a monochromator.
Experiments on D
2 molecules have been conducted using the 9th or
the 11th
harmonic as the pump pulse. Novel dissociative ionization
pathways via highly excited states of D
2 have been revealed, thus
suggesting potential applications for time-resolved studies and
control of photochemistry processes.
Advisors/Committee Members: Itzhak Ben-Itzhak and Charles Lewis Cocke.
Subjects/Keywords: High
harmonic generation;
COLTRIMS; Ultrafast
dynamics;
Pump-probe; Atomic Physics (0748); Optics (0752)
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APA ·
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Manager
APA (6th Edition):
Cao, W. (2014). Pump-probe
study of atoms and small molecules with laser driven high order
harmonics. (Doctoral Dissertation). Kansas State University. Retrieved from http://hdl.handle.net/2097/18161
Chicago Manual of Style (16th Edition):
Cao, Wei. “Pump-probe
study of atoms and small molecules with laser driven high order
harmonics.” 2014. Doctoral Dissertation, Kansas State University. Accessed April 16, 2021.
http://hdl.handle.net/2097/18161.
MLA Handbook (7th Edition):
Cao, Wei. “Pump-probe
study of atoms and small molecules with laser driven high order
harmonics.” 2014. Web. 16 Apr 2021.
Vancouver:
Cao W. Pump-probe
study of atoms and small molecules with laser driven high order
harmonics. [Internet] [Doctoral dissertation]. Kansas State University; 2014. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/2097/18161.
Council of Science Editors:
Cao W. Pump-probe
study of atoms and small molecules with laser driven high order
harmonics. [Doctoral Dissertation]. Kansas State University; 2014. Available from: http://hdl.handle.net/2097/18161
29.
Helal, Ahmed Mohammed.
Explosion dynamics of van der Waals clusters using 38 nm XUV laser pulses: Explosion dynamics of van der Waals clusters using 38 nm extreme ultraviolet laser pulses.
Degree: PhD, Physics, 2016, University of Texas – Austin
URL: http://hdl.handle.net/2152/41570
► The interaction of intense XUV laser pulses with matter and rare gas cluster has been the focus of the scientific c community for decades. This…
(more)
▼ The interaction of intense XUV laser pulses with matter and rare gas cluster
has been the focus of the scientific c community for decades. This focus has been sparked by the ongoing efforts to reach microscopy with atomic resolution, leading to
a time resolved image on the scale of the atomic motion.
The interest in van der Waals clusters appears due to it's similarity with the
small bio-molecules, studying the behavior of these cluster will shed some light on
how the biomolecules behavior under intense laser pulse.
We have conducted a major upgrade to the UT THOR laser system, that
enables us to achieve 17.7 nJ of XUV energy, produced by
high harmonic generation,
which is used to conduct multiple cluster experiments.
We investigated the dynamics of rare-gas clusters produced by Ar and Xe
gases, the ion time of
flight, kinetic energy and electron energy have been measured,
the
generation of ion kinetic energy of two di different temperatures (6 and 55 eV) due
to hydrodynamic expansion was observed.
viii
For Xe clusters, we observed the
generation of unexplained
high charge states
up to Xe
9+, that could be due to the effect of continuum lowering and inner ionization
of the giant resonance 4d-level.
We also investigated the dynamics of small molecule clusters. Stating with
nitrogen clusters, we noticed a dependence of the ionization ratio between N+
2 and
N+on the cluster size has been noticed. In addition to that nitrogen clusters shows
the highest ion kinetic energy generated between all the clusters investigated in this
dissertation.
The interaction of XUV laser pulses with Methane cluster is studied, we could
not detect any
high charges of methane fragments such as (CH2+
4 ). However, we noticed
that we generated multiple fragments by breaking C-H bonds (CH+3 ;CH+
2 ;CH+) in addition to bare carbon with
high cluster sizes. The
generation of CH+5 , H+ and H+2 was also observed. Studying the partial yield of each of these reveals that the
correlation between CH+
5 and H+ is opposite to what is expected, which might be
due to the change of the cluster properties or the expansion dynamic itself (towards
more hydrodynamics).
Advisors/Committee Members: Ditmire, Todd (advisor), Keto, John W. (advisor), Bengtson, Roger D (committee member), Downer, Michael (committee member), Ben-Yakar, Adela (committee member).
Subjects/Keywords: Clusters; XUV; Extreme ultraviolet laser; HHG; High order harmonic generation; Xe; Ar; Methane
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APA ·
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MLA ·
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CSE |
Export
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Manager
APA (6th Edition):
Helal, A. M. (2016). Explosion dynamics of van der Waals clusters using 38 nm XUV laser pulses: Explosion dynamics of van der Waals clusters using 38 nm extreme ultraviolet laser pulses. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/41570
Chicago Manual of Style (16th Edition):
Helal, Ahmed Mohammed. “Explosion dynamics of van der Waals clusters using 38 nm XUV laser pulses: Explosion dynamics of van der Waals clusters using 38 nm extreme ultraviolet laser pulses.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed April 16, 2021.
http://hdl.handle.net/2152/41570.
MLA Handbook (7th Edition):
Helal, Ahmed Mohammed. “Explosion dynamics of van der Waals clusters using 38 nm XUV laser pulses: Explosion dynamics of van der Waals clusters using 38 nm extreme ultraviolet laser pulses.” 2016. Web. 16 Apr 2021.
Vancouver:
Helal AM. Explosion dynamics of van der Waals clusters using 38 nm XUV laser pulses: Explosion dynamics of van der Waals clusters using 38 nm extreme ultraviolet laser pulses. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Apr 16].
Available from: http://hdl.handle.net/2152/41570.
Council of Science Editors:
Helal AM. Explosion dynamics of van der Waals clusters using 38 nm XUV laser pulses: Explosion dynamics of van der Waals clusters using 38 nm extreme ultraviolet laser pulses. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/41570
University of Colorado
30.
Gardner, Dennis Floyd, Jr.
Coherent Diffractive Imaging Near the Spatio-Temporal Limit with High-Harmonic Sources.
Degree: PhD, 2017, University of Colorado
URL: https://scholar.colorado.edu/phys_gradetds/194
► This thesis discusses methods for high-resolution static and stroboscopic microscopy using tabletop coherent extreme ultraviolet (EUV) radiation from tabletop high-harmonic generation (HHG) sources. These…
(more)
▼ This thesis discusses methods for
high-resolution static and stroboscopic microscopy using tabletop coherent extreme ultraviolet (EUV) radiation from tabletop
high-
harmonic generation (HHG) sources. These coherent short wavelength light sources are combined with a lensless, computational, phase and amplitude-contrast technique called ptychographic Coherent Diffractive Imaging (CDI). While ptychographic CDI techniques are currently widespread for visible, EUV and X-ray microscopy, no previous work has been able to achieve at-wavelength resolution of extended samples, especially in a reflection geometry, nor has previous work been able to image periodic samples with
high-fidelity. In this work, a combination of experimental methods for
high-numerical aperture imaging and novel computational algorithms enabled the highest resolution-to-wavelength demonstrations using any CDI technique. These algorithms include tilted plane correction, which enables
high-resolution imaging of surfaces in a reflection geometry, and a powerful technique termed ‘modulus enforced probe’, which enables both imaging of periodic objects and convergence of the ptychographic CDI algorithm in fewer iterations. Furthermore, the ultrafast pulse duration of the
high-
harmonic radiation is harnessed to demonstrate proof-of-principle pump-probe imaging of nanostructures, capturing thermal transport processes in nanostructures with an axial resolution of 3 angstroms. Stroboscopic imaging with nanoscale resolution is a critical tool for the investigation of nanoscale heat flow and magnetic switching for the advancement of next
generation nano-electronics, data storage, and nano-engineered systems.
Advisors/Committee Members: Margaret M. Murnane, Henry C. Kapteyn, Daniel E. Adams, Ivan I. Smalyukh, Mark Hernandez.
Subjects/Keywords: coherent diffractive imaging; computational imaging; extreme ultraviolet EUV; high harmonic generation; high-resolution microscopy; ptychography; Nanotechnology; Optics; Physics
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APA (6th Edition):
Gardner, Dennis Floyd, J. (2017). Coherent Diffractive Imaging Near the Spatio-Temporal Limit with High-Harmonic Sources. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/phys_gradetds/194
Chicago Manual of Style (16th Edition):
Gardner, Dennis Floyd, Jr. “Coherent Diffractive Imaging Near the Spatio-Temporal Limit with High-Harmonic Sources.” 2017. Doctoral Dissertation, University of Colorado. Accessed April 16, 2021.
https://scholar.colorado.edu/phys_gradetds/194.
MLA Handbook (7th Edition):
Gardner, Dennis Floyd, Jr. “Coherent Diffractive Imaging Near the Spatio-Temporal Limit with High-Harmonic Sources.” 2017. Web. 16 Apr 2021.
Vancouver:
Gardner, Dennis Floyd J. Coherent Diffractive Imaging Near the Spatio-Temporal Limit with High-Harmonic Sources. [Internet] [Doctoral dissertation]. University of Colorado; 2017. [cited 2021 Apr 16].
Available from: https://scholar.colorado.edu/phys_gradetds/194.
Council of Science Editors:
Gardner, Dennis Floyd J. Coherent Diffractive Imaging Near the Spatio-Temporal Limit with High-Harmonic Sources. [Doctoral Dissertation]. University of Colorado; 2017. Available from: https://scholar.colorado.edu/phys_gradetds/194
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