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1.
Persuy, Déborah.
Nanoscopie résolue en temps : étude de la réponse spatiale et temporelle pour l'imagerie ultra-rapide : Time resolved nanoscopy : spatial and temporal study for ultra-fast imaging.
Degree: Docteur es, Physique, 2015, Université de Strasbourg
URL: http://www.theses.fr/2015STRAE016
► Nous nous intéressons au développement ainsi qu’à la modélisation théorique de techniques de spectroscopie optique de champ lointain capables de coupler résolutions spatiale et temporelle…
(more)
▼ Nous nous intéressons au développement ainsi qu’à la modélisation théorique de techniques de spectroscopie optique de champ lointain capables de coupler résolutions spatiale et temporelle grâce à l’utilisation de faisceaux d'excitation mis en forme spatialement. Nous établissons, théoriquement et expérimentalement, que dans une expérience de mélange de quatre ondes réalisée avec des faisceaux de Laguerre-Gauss, la charge totale du moment orbital est conservée. Nous montrons comment cette propriété peut être mise à profit pour travailler en géométrie colinéaire dans le but d’améliorer la résolution spatiale des expériences. Dans une deuxième partie, nous présentons une technique de spectroscopie « pompe-sonde » résolue spatialement que nous avons conçue et développée : l’imagerie temporelle est obtenue via la détection interférométrique des variations d’indice d’un matériau vues par une sonde étendue et consécutives à l’excitation par une impulsion pompe focalisée à la limite de diffraction. Nos modélisations démontre d’un tel montage associé à l’emploi d’une impulsion pompe modulée spatialement doit permettre, grâce au battement entre les fréquences spatiales des inhomogénéités de l’échantillon et de la modulation spatiale de l’excitation, de dépasser la limite de Rayleigh.
This work focuses on developing and modelling far-field spectroscopic methods that couple spatial and time resolutions by using beam-shaping. In a first part, we demonstrate, theoretically and experimentally, that generating a signal in a four-wave mixing experiment performed with Laguerre-Gauss beams, implies the conservation of the total charge of the orbital momentum. We show that this specificity can be used to perform experiments with collinear beams in order to improve spatial resolution. In a second part, we present a time- and spatially-resolved pump-probe technique of our own design: time-resolved imaging is obtained by the interferometric detection of variations in the refraction index of a material, undergone by a wide probe and induced by a diffraction-limited pump-pulse. Improving such an experiment set-up with a spatially-modulated pump-pulse should enable, thanks to the beating between spatial frequencies of sample inhomogeneities and the excitation spatial-modulation, to increase spatial resolution go the Rayleigh criterion.
Advisors/Committee Members: Hönerlage, Bernd (thesis director).
Subjects/Keywords: Spectroscopie ultra-rapide; Imagerie; Hyper-résolution; Non-linéarités optiques; Ultra-fast spectroscopy; Imaging; Microscopy; Optical non-linearities; 535.84; 616.07
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APA ·
Chicago ·
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APA (6th Edition):
Persuy, D. (2015). Nanoscopie résolue en temps : étude de la réponse spatiale et temporelle pour l'imagerie ultra-rapide : Time resolved nanoscopy : spatial and temporal study for ultra-fast imaging. (Doctoral Dissertation). Université de Strasbourg. Retrieved from http://www.theses.fr/2015STRAE016
Chicago Manual of Style (16th Edition):
Persuy, Déborah. “Nanoscopie résolue en temps : étude de la réponse spatiale et temporelle pour l'imagerie ultra-rapide : Time resolved nanoscopy : spatial and temporal study for ultra-fast imaging.” 2015. Doctoral Dissertation, Université de Strasbourg. Accessed March 09, 2021.
http://www.theses.fr/2015STRAE016.
MLA Handbook (7th Edition):
Persuy, Déborah. “Nanoscopie résolue en temps : étude de la réponse spatiale et temporelle pour l'imagerie ultra-rapide : Time resolved nanoscopy : spatial and temporal study for ultra-fast imaging.” 2015. Web. 09 Mar 2021.
Vancouver:
Persuy D. Nanoscopie résolue en temps : étude de la réponse spatiale et temporelle pour l'imagerie ultra-rapide : Time resolved nanoscopy : spatial and temporal study for ultra-fast imaging. [Internet] [Doctoral dissertation]. Université de Strasbourg; 2015. [cited 2021 Mar 09].
Available from: http://www.theses.fr/2015STRAE016.
Council of Science Editors:
Persuy D. Nanoscopie résolue en temps : étude de la réponse spatiale et temporelle pour l'imagerie ultra-rapide : Time resolved nanoscopy : spatial and temporal study for ultra-fast imaging. [Doctoral Dissertation]. Université de Strasbourg; 2015. Available from: http://www.theses.fr/2015STRAE016
2.
Salles, Sébastien.
Estimation du mouvement de la paroi carotidienne en imagerie ultrasonore par une approche de marquage ultrasonore : Motion estimation of the carotid wall in ultrasound imaging using transverses oscillations.
Degree: Docteur es, Acoustique et traitement de signal/image, 2015, INSA Lyon
URL: http://www.theses.fr/2015ISAL0092
► Ce travail de thèse est axé sur le domaine du traitement d’images biomédicales. L’objectif de notre étude est l’estimation des paramètres traduisant les propriétés mécaniques…
(more)
▼ Ce travail de thèse est axé sur le domaine du traitement d’images biomédicales. L’objectif de notre étude est l’estimation des paramètres traduisant les propriétés mécaniques de l’artère carotide in vivo en imagerie échographique, dans une optique de détection précoce des pathologies cardiovasculaires. L’étude des comportements dynamiques de l’artère pour le dépistage précoce de l’athérosclérose constitue à ce jour une piste privilégiée. Cependant, malgré les avancées récentes, l’estimation du mouvement de la paroi carotidienne reste toujours difficile, notamment dans la direction longitudinale (direction parallèle au vaisseau). L’élaboration d’une méthode innovante permettant d’étudier le mouvement de la paroi carotidienne constitue la principale motivation de ce travail de thèse. Les trois contributions principales proposées dans ce travail sont i) le développement, la validation, et l’évaluation clinique d’une méthode originale d’estimation de mouvement 2D adaptée au mouvement de la paroi carotidienne, ii) la validation en simulation, et expérimentale de l’extension à la 3D de la méthode d’estimation proposée, et iii) l’évaluation expérimentale de la méthode proposée, en imagerie ultrasonore ultra-rapide, dans le cadre de l’estimation locale de la vitesse de l’onde de pouls. Nous proposons une méthode d’estimation de mouvement combinant un marquage ultrasonore dans la direction latérale, et un estimateur de mouvement basé sur la phase des images ultrasonores. Le marquage ultrasonore est réalisé par l’intermédiaire d’oscillations transverses. Nous proposons deux approches différentes pour introduire ces oscillations transverses, une approche classique utilisant une fonction de pondération spécifique, et une approche originale par filtrage permettant de contrôler de manière optimale leurs formations. L’estimateur de mouvement proposé utilise les phases analytiques des images radiofréquences, extraites par l’approche de Hahn. Ce travail de thèse montre que la méthode proposée permet une estimation de mouvement plus précise dans la direction longitudinale, et plus généralement dans les directions perpendiculaires au faisceau ultrasonore, que celle obtenue avec d’autres méthodes plus traditionnelles. De plus, l’évaluation expérimentale de la méthode sur des séquences d’images ultrasonores ultra-rapides issues de fantômes de carotide, a permis l’estimation locale de la vitesse de propagation de l’onde de pouls, la mise en évidence de la propagation d’un mouvement longitudinal et enfin l’estimation du module de Young des vaisseaux.
This work focuses on the processing of biomedical images. The aim of our study is to estimate the mechanical properties of the carotid artery in vivo using ultrasound imaging, in order to detect cardiovascular diseases at an early stage. Over the last decade, researchers have shown interest in studying artery wall motion, especially the motion of the carotid intima-media complex in order to demonstrate its significance as a marker of Atherosclerosis. However, despite recent progress, motion…
Advisors/Committee Members: Bou-Saïd, Benyebka (thesis director), Vray, Didier (thesis director).
Subjects/Keywords: Imagerie médicale; Imagerie ultrasonore; Imagerie ultrasonore 3D; Imagerie 2D; Estimation de mouvement; Oscillation transversale; Imagerie ultra-Rapide; Onde pouls; Carotide; Medical Imaging; Ultrasound Imaging; Carotid; Motion estimation; Transverse oscillation; Ultra fast imaging; Pulse wave velocity; 2D Imaging; 3D Imaging; 616.075 430 72
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Salles, S. (2015). Estimation du mouvement de la paroi carotidienne en imagerie ultrasonore par une approche de marquage ultrasonore : Motion estimation of the carotid wall in ultrasound imaging using transverses oscillations. (Doctoral Dissertation). INSA Lyon. Retrieved from http://www.theses.fr/2015ISAL0092
Chicago Manual of Style (16th Edition):
Salles, Sébastien. “Estimation du mouvement de la paroi carotidienne en imagerie ultrasonore par une approche de marquage ultrasonore : Motion estimation of the carotid wall in ultrasound imaging using transverses oscillations.” 2015. Doctoral Dissertation, INSA Lyon. Accessed March 09, 2021.
http://www.theses.fr/2015ISAL0092.
MLA Handbook (7th Edition):
Salles, Sébastien. “Estimation du mouvement de la paroi carotidienne en imagerie ultrasonore par une approche de marquage ultrasonore : Motion estimation of the carotid wall in ultrasound imaging using transverses oscillations.” 2015. Web. 09 Mar 2021.
Vancouver:
Salles S. Estimation du mouvement de la paroi carotidienne en imagerie ultrasonore par une approche de marquage ultrasonore : Motion estimation of the carotid wall in ultrasound imaging using transverses oscillations. [Internet] [Doctoral dissertation]. INSA Lyon; 2015. [cited 2021 Mar 09].
Available from: http://www.theses.fr/2015ISAL0092.
Council of Science Editors:
Salles S. Estimation du mouvement de la paroi carotidienne en imagerie ultrasonore par une approche de marquage ultrasonore : Motion estimation of the carotid wall in ultrasound imaging using transverses oscillations. [Doctoral Dissertation]. INSA Lyon; 2015. Available from: http://www.theses.fr/2015ISAL0092

University of Maryland
3.
Zhao, Kun.
Ultra-fast Dynamics of Small Molecules in Strong Fields.
Degree: Chemical Physics, 2006, University of Maryland
URL: http://hdl.handle.net/1903/3444
► Correlation detection techniques (image labeling, coincidence imaging, and joint variance) are developed with an image spectrometer capable of collecting charges ejected over 4π sr and…
(more)
▼ Correlation detection techniques (image labeling, coincidence
imaging, and joint variance) are developed with an image spectrometer capable of collecting charges ejected over 4π sr and a digital camera synchronized with the laser repetition rate at up to 735 Hz. With these techniques, molecular decay channels ejecting atomic fragments with different momenta (energies) can be isolated; thus the initial molecular configurations (bond lengths and/or bond angles) and orientations as well as their distributions can be extracted. These techniques are applied to study strong-field induced dynamics of diatomic and triatomic molecules.
Specific studies included the measurements of the Coulomb explosion energy as a function of bond angle in linear (CO
2) and bent (NO
2) triatomics and the ejection anisotropy relative to the laser polarization axis during Coulomb explosions in both triatomic (CO
2 and NO
2) and diatomic (H
2, N
2 and O
2) systems. The experiments were performed with 100 fs, 800 nm laser pulses focused to 0.1 ~ 5 × 10
15 W/cm
2.
The explosion energy of NO
2 decreases monotonically by more than 25% from the smallest to the largest bond angle. By contrast, the CO
2 explosion energies are nearly independent of bond angle. The enhanced-ionization and static-screening models in two-dimension with three charge centers were developed to simulate the explosion energies as a function of bond angle. The predictions are consistent with the measurements of CO
2 and NO
2. The observed explosion signals as a function of bond angle for both triatomics show large-amplitude vibrations.
The ejection angular distributions in triatomic (CO
2 and NO
2) and diatomic (H
2, N
2, and O
2) Coulomb explosions were measured; the contribution made to the ejection anisotropy by dynamic alignment was studied by comparing the images obtained with linearly and circularly polarized fields. Different angular distributions of the molecules are consistent with different ionization stages, induced dipole moments and rotational constants. The dynamic alignment of H
2 is found to be nearly complete. A larger dynamic alignment of CO
2 than that of N
2 or O
2 is consistent with that more electrons have been removed from CO
2 and the precursor molecular ion spends more time in the field prior to the explosion.
Advisors/Committee Members: Hill, Wendell T (advisor).
Subjects/Keywords: Physics, Molecular; Physics, Optics; ultra-fast; molecular dynamics; intense field; Coulomb explosion; imaging; correlation detection
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zhao, K. (2006). Ultra-fast Dynamics of Small Molecules in Strong Fields. (Thesis). University of Maryland. Retrieved from http://hdl.handle.net/1903/3444
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):
Zhao, Kun. “Ultra-fast Dynamics of Small Molecules in Strong Fields.” 2006. Thesis, University of Maryland. Accessed March 09, 2021.
http://hdl.handle.net/1903/3444.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Zhao, Kun. “Ultra-fast Dynamics of Small Molecules in Strong Fields.” 2006. Web. 09 Mar 2021.
Vancouver:
Zhao K. Ultra-fast Dynamics of Small Molecules in Strong Fields. [Internet] [Thesis]. University of Maryland; 2006. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/1903/3444.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Zhao K. Ultra-fast Dynamics of Small Molecules in Strong Fields. [Thesis]. University of Maryland; 2006. Available from: http://hdl.handle.net/1903/3444
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

York University
4.
Carlse, Gehrig Michael Isaac.
Techniques for Mass Determination of Airborne Micro-Particles in an Optical Dipole Force Trap.
Degree: MSc -MS, Physics And Astronomy, 2020, York University
URL: http://hdl.handle.net/10315/37892
► We present the development of a new technique for rapidly measuring the masses of airborne particles confined in free space optical dipole force traps. This…
(more)
▼ We present the development of a new technique for rapidly measuring the masses of airborne particles confined in free space optical dipole force traps. This technique employs an ultrafast CMOS sensor with a wide field of view to image the real time motion of trapped particles on timescales in which diffusive Brownian motion predicted by Einstein makes a transition to ballistic motion. The technique relies on direct
imaging of drop-and-restore experiments without the need for a vacuum environment. In these drop-and-restore experiments, the trapping light is rapidly shuttered with an acousto-optic modulator causing the particle to be released from and subsequently recaptured by the trapping force. The trajectories from the falls and restorations are combined to infer the particle mass, which we also corroborate using an analysis of position autocorrelation functions of the trapped particles. Using the drop-and-restore technique, we report a statistical uncertainty of less than 2% for masses on the order of 510^(14) kg, using a data acquisition time of approximately 90 seconds. We also show that the measurement of a ballistic mean-squared displacement can be used for a preliminary estimate of the mass of a trapped micro-particle. Furthermore, we show that even the capacity to detect the timescale at which the transition to ballistic motion occurs, in combination with a measurement of particle size, can provide a similar mass estimate, consistent with the more rigorous mass determinations developed in this thesis. Ultimately, the methods presented here constitute simple, effective, and competitive alternatives for characterizing trapped particles and measuring their masses, in comparison with more elaborate standard techniques.
Advisors/Committee Members: Kumarakrishnan, Anantharaman (advisor).
Subjects/Keywords: Atomic physics; Optical tweezers; Optical trapping; Lasers; Laser trapping; Brownian motion; Diffusion; Micro-particles; Micro-scale motion; Ultra-fast imaging; Imaging; Statistical physics; Spectroscopy; Mass determination; Autocorrelation; Power spectral density; Precision measurement; Physics; Biophysics; Applied physics; Harmonic oscillator; Particle tracking; Video microscopy; PSD; PACF; Release and recapture; Drop and restore; Free space trapping
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Carlse, G. M. I. (2020). Techniques for Mass Determination of Airborne Micro-Particles in an Optical Dipole Force Trap. (Masters Thesis). York University. Retrieved from http://hdl.handle.net/10315/37892
Chicago Manual of Style (16th Edition):
Carlse, Gehrig Michael Isaac. “Techniques for Mass Determination of Airborne Micro-Particles in an Optical Dipole Force Trap.” 2020. Masters Thesis, York University. Accessed March 09, 2021.
http://hdl.handle.net/10315/37892.
MLA Handbook (7th Edition):
Carlse, Gehrig Michael Isaac. “Techniques for Mass Determination of Airborne Micro-Particles in an Optical Dipole Force Trap.” 2020. Web. 09 Mar 2021.
Vancouver:
Carlse GMI. Techniques for Mass Determination of Airborne Micro-Particles in an Optical Dipole Force Trap. [Internet] [Masters thesis]. York University; 2020. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10315/37892.
Council of Science Editors:
Carlse GMI. Techniques for Mass Determination of Airborne Micro-Particles in an Optical Dipole Force Trap. [Masters Thesis]. York University; 2020. Available from: http://hdl.handle.net/10315/37892
5.
McCormick, Elizabeth Joan, McCormick.
Optical Properties of Two Dimensional Semiconductors.
Degree: PhD, Physics, 2018, The Ohio State University
URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1531907387651019
► Two dimensional materials (2D) have become a huge research focus in recent history due to the interesting properties and phenomena that occur with reduced dimensionality.…
(more)
▼ Two dimensional materials (2D) have become a huge
research focus in recent history due to the interesting properties
and phenomena that occur with reduced dimensionality. Additionally,
the reduced size of these materials, the plethora of different
properties available in the 2D arsenal, and the ability to
relatively easily combine different 2D materials makes them
extremely promising for nanodevices and future computing
architectures. Here, we investigate the optical properties of two
different 2D semiconductors, germanane and transition metal
dichalcogenides (TMDs). We focus on the band gap and band edge
physics in thin film germanane, a topic that is largely unexplored.
We are able to grow thin films of germanane and transfer them onto
insulating substrates, a critical step for opto-electronic
applications and investigations. Using a combination of optical and
opto-electronic techniques including photoconductivity, absorption
spectroscopy, and photoluminescence, we are able to investigate the
band gap, as well as determine the existence of band tail and
defect states in the gap. Having an understanding of the band gap
is necessary for future electronic and opto-electronic
applications, as many of the interesting properties of a
semiconductor are highly dependent on the band gap. Transition
metal dichalcogenides have very interesting spin/valley properties
due to the large spin-orbit coupling and existence of
non-equivalent valleys in their band structure. We investigate the
long spin and valley lifetimes in tungsten disulphide, a member of
the TMD family, using time resolved Kerr rotation (TRKR) microscopy
and photoluminescence microscopy. Our unique approach provides
insight into the role of dark trions in the long spin and valley
lifetimes, in addition to the transfer of angular momentum to
resident carriers in the material. We also find that the strong
spin-orbit coupling leads to spins robust against in-plane external
magnetic fields. In order to study the unique spin and valley
transport in TMDs, including the valley Hall effect, we developed a
spatially offset time resolved Kerr rotation microscopy system,
which allows spins and valleys to be excited in one location and
probed in another. Preliminary data on spin/valley diffusion in
tungsten diselenide, another member of the TMD family, is
presented, with a discussion of the substrate effect on diffusion
in WSe2. These studies enable an unprecedented microscopic
understanding of spin and valley dynamics in TMDs, a crucial
component in developing future nanoscale spintronic and
valleytronic applications.
Advisors/Committee Members: Kawakami, Roland (Advisor).
Subjects/Keywords: Condensed Matter Physics; Optics; Physics; Transition Metal Dichalcogenides; TMD; ultra-fast optics; TRKR; time resolved Kerr rotation; imaging; germanane; 2D; spin dynamics; valley dynamics; photoluminescence, spin lifetime
…Kawakami, “Imaging Spin
Dynamics in Monolayer WS2 by Time-Resolved Kerr Rotation Microscopy,” 2D… …78
ix
Chapter 5. Imaging Spin Dynamics in Monolayer WS2 using Time Resolved Kerr
Rotation… …83
5.4 High Resolution Imaging of Spin and Valley Dynamics… …rotation at short time delays. An exponential
fit to the fast decay (green curve)… …an easily accessible ultra thin material
that can maintain and transport spin extremely…
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
McCormick, Elizabeth Joan, M. (2018). Optical Properties of Two Dimensional Semiconductors. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1531907387651019
Chicago Manual of Style (16th Edition):
McCormick, Elizabeth Joan, McCormick. “Optical Properties of Two Dimensional Semiconductors.” 2018. Doctoral Dissertation, The Ohio State University. Accessed March 09, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1531907387651019.
MLA Handbook (7th Edition):
McCormick, Elizabeth Joan, McCormick. “Optical Properties of Two Dimensional Semiconductors.” 2018. Web. 09 Mar 2021.
Vancouver:
McCormick, Elizabeth Joan M. Optical Properties of Two Dimensional Semiconductors. [Internet] [Doctoral dissertation]. The Ohio State University; 2018. [cited 2021 Mar 09].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1531907387651019.
Council of Science Editors:
McCormick, Elizabeth Joan M. Optical Properties of Two Dimensional Semiconductors. [Doctoral Dissertation]. The Ohio State University; 2018. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1531907387651019
.