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Texas A&M University
1.
Almethen, Abdurrahman Abdullah A.
Engineering of Fluorescence Nanodiamonds in a Plasma Discharge.
Degree: PhD, Physics, 2018, Texas A&M University
URL: http://hdl.handle.net/1969.1/173349 
► The fourth state of matter (plasma state) was first discovered in an electrical discharge tube (Crookes tube) and named as a radiant matter in 1879…
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▼ The fourth state of matter (plasma state) was first discovered in an electrical discharge tube (Crookes tube) and named as a radiant matter in 1879 by Sir William Crookes. Nowadays, plasma discharges have innumerable uses in several fields such as material processing, growth, etc. Plasma discharges can be created by electric fields that are AC, DC, Radio Frequency (RF), or Microwave (MW) or a combination, depending on the applications. Examples of plasma applications include growth by plasma-enhanced chemical vapor deposition (PECVD), etching, sputtering, implantation, and oxidation. For RF plasmas, either inductive and capacitive coupling can be used, and are common for synthesizing nanomaterial in the gas phase or in plasma-liquid interactions.
For plasma assisted growth of diamonds, either homogeneous and heterogeneous nucleation mechanisms can occur depending on the type of plasma discharge and other reaction conditions. For example, growth can be at high pressure, atmospheric pressure, and low pressure. Starting materials for nanodiamonds (NDs) can be hydrocarbons like ethanol (C₂H₆O) or low molecular weight hydrocarbons like CH₄ and C₂H₄.
For more controlled growth, diamondoids like Adamantane (C₁₀H₁₆), can be used as diamond seeds because they resemble a single lattice unit of diamond. Recently, more complex diamondoids as seeds such as pentamentane (C₂₆H₃₂) have been employed for constructing NDs with high efficiency by MW plasma chemical vapor deposition (CVD).
The present work is a study that focuses on nucleation, engineering, and size controlling of NDs; it is motivated by the need to develop more controlled techniques for synthesizing or growing NDs especially for the formation of nitrogen-vacancy (N-V⁻) and silicon-vacancy (Si-V) centers. Based on the type of plasma source, the work was divided among three main projects. The first one was centered on studying the DC plasma discharge method at short and long distances between the electrodes as well as at various levels of vacuum. The second project concentrated on manufacturing NDs by applying capacitively coupled RF plasma discharges under various conditions. The third project involved the use of microwave plasma.
Advisors/Committee Members: Sokolov, Alexei V. (advisor), Hemmer, Phillip R. (advisor), Zubairy, M. Suhail (committee member), Zheltikov, Aleksei M. (committee member).
Subjects/Keywords: nanodiamonds growth; chemical vapor deposition; plasma discharges; fluorescent nanodiamond; nitrogen-vacancy center; biocompatibility; bioimaging; biosensing.
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APA (6th Edition):
Almethen, A. A. A. (2018). Engineering of Fluorescence Nanodiamonds in a Plasma Discharge. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/173349
Chicago Manual of Style (16th Edition):
Almethen, Abdurrahman Abdullah A. “Engineering of Fluorescence Nanodiamonds in a Plasma Discharge.” 2018. Doctoral Dissertation, Texas A&M University. Accessed January 19, 2021.
http://hdl.handle.net/1969.1/173349.
MLA Handbook (7th Edition):
Almethen, Abdurrahman Abdullah A. “Engineering of Fluorescence Nanodiamonds in a Plasma Discharge.” 2018. Web. 19 Jan 2021.
Vancouver:
Almethen AAA. Engineering of Fluorescence Nanodiamonds in a Plasma Discharge. [Internet] [Doctoral dissertation]. Texas A&M University; 2018. [cited 2021 Jan 19].
Available from: http://hdl.handle.net/1969.1/173349.
Council of Science Editors:
Almethen AAA. Engineering of Fluorescence Nanodiamonds in a Plasma Discharge. [Doctoral Dissertation]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/173349
2.
Springer, Matthew M.
Time-resolved Characterization of Ultrashort Pulse Propagation.
Degree: PhD, Physics, 2013, Texas A&M University
URL: http://hdl.handle.net/1969.1/151868
► The propagation of ultrashort femtosecond laser pulses in linear dielectric materials is determined in the time, space, and frequency domains by linear Maxwell optics through…
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▼ The propagation of ultrashort femtosecond laser pulses in linear dielectric materials is determined in the time, space, and frequency domains by linear Maxwell optics through dispersion and diffraction. For intense pulses, pulse propagation is additionally modified by nonlinearities in the medium such as the optical Kerr effect, plasma generation, and self-phase modulation.
In this work we report the results of several experiments on the propagation of ultrashort pulses. In the linear regime, we characterize the temporal evolution of an ultrashort pulse during propagation through a linear dielectric under anomalous dispersion. Under these conditions the pulse evolution departs from the group velocity and group delay dispersion approximations, which leads to the formation of optical precursors. We describe an experiment which observes the propagation of optical precursors in a bulk condensed-matter dielectric. We generate ultrashort laser pulses and propagate the pulses through a bulk dye with an absorption resonance turned to the center wavelength of the femotsecond pulse. The pulse is then characterized in the time domain before and after propagation. Through numerical simulation we verify that the behavior of the precursors in the temporal pulse profile corresponds with the classical model.
Under very high intensity laser pulses, the nonlinearities induced by the propagation of the intense ultrashort pulse produce changes in the complex refractive index of the nonlinear material. We report the results of experiments involving time- resolved imaging of the propagation of ultrashort pulses in dielectric materials. We experimentally observe and characterize these effects through a weak-probe imaging effect which directly measures the nonlinearity in a time-resolved manner. In these experiments an intense femtosecond laser pulse is propagated in a nonlinear intensity regime while an unfocused low-intensity femtosecond pulse is used as to probe the nonlinear pulse. We use this technique to characterize femtosecond pulses in air and liquid, especially in the regime of optical filamentation. We subsequently calculate parameters such as the plasma density, the transverse extent, and the instantaneous refractive index within the femtosecond laser filament under conditions which are not accessible through most standard pulse measurement techniques.
Advisors/Committee Members: Sokolov, Alexei V (advisor), Kattawar, George W (committee member), Fry, Edward S (committee member), Hemmer, Phillip R (committee member).
Subjects/Keywords: Femtosecond Filamentation; Optical Precursors
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APA ·
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APA (6th Edition):
Springer, M. M. (2013). Time-resolved Characterization of Ultrashort Pulse Propagation. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/151868
Chicago Manual of Style (16th Edition):
Springer, Matthew M. “Time-resolved Characterization of Ultrashort Pulse Propagation.” 2013. Doctoral Dissertation, Texas A&M University. Accessed January 19, 2021.
http://hdl.handle.net/1969.1/151868.
MLA Handbook (7th Edition):
Springer, Matthew M. “Time-resolved Characterization of Ultrashort Pulse Propagation.” 2013. Web. 19 Jan 2021.
Vancouver:
Springer MM. Time-resolved Characterization of Ultrashort Pulse Propagation. [Internet] [Doctoral dissertation]. Texas A&M University; 2013. [cited 2021 Jan 19].
Available from: http://hdl.handle.net/1969.1/151868.
Council of Science Editors:
Springer MM. Time-resolved Characterization of Ultrashort Pulse Propagation. [Doctoral Dissertation]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/151868
Texas A&M University
3.
Anisimov, Petr Mikhailovich.
Quantum coherence phenomena in x-ray optics.
Degree: PhD, Physics, 2009, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-3039
► The effects of quantum coherence in X-ray optics at nuclear transitions are investigated from a theoretical point of view. First, we introduce the general concept…
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▼ The effects of quantum coherence in X-ray optics at nuclear transitions are
investigated from a theoretical point of view. First, we introduce the general concept
of the decaying dressed states and present a classification of the quantum coherence
effects in a three-level coherently driven system. Second, we show that the interference
effects may appear in X-ray radiation at the nuclear transitions under the condition of
the nuclear level anti-crossing. This effects are similar to electromagnetically induced
transparency, which has been widely studied earlier at the electronic transitions in
optics. We also suggest a new technique for inhomogeneous line narrowing at nuclear
transitions. This technique is based on the combined action of RF and DC fields
and adopted to be applied in the M¨ossbauer spectroscopy. Numerical simulation of a
simple model with the dipole-dipole interaction is presented in order to demonstrate
the efficiency of the technique. Finally, we study the possibility to suppress the nuclear
elastic forward scattering in the synchrotron experiments using trains of pulses. A
numerical model is developed to confirm this possibility and the main issue of relative
phases of consecutive pulses is discussed.
Advisors/Committee Members: Kocharovskaya, Olga (advisor), Belyanin, Alexey (committee member), Hemmer, Phillip R (committee member), Rostovtsev, Yuri (committee member).
Subjects/Keywords: Quantum coherence; Mossbauer
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APA ·
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APA (6th Edition):
Anisimov, P. M. (2009). Quantum coherence phenomena in x-ray optics. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-3039
Chicago Manual of Style (16th Edition):
Anisimov, Petr Mikhailovich. “Quantum coherence phenomena in x-ray optics.” 2009. Doctoral Dissertation, Texas A&M University. Accessed January 19, 2021.
http://hdl.handle.net/1969.1/ETD-TAMU-3039.
MLA Handbook (7th Edition):
Anisimov, Petr Mikhailovich. “Quantum coherence phenomena in x-ray optics.” 2009. Web. 19 Jan 2021.
Vancouver:
Anisimov PM. Quantum coherence phenomena in x-ray optics. [Internet] [Doctoral dissertation]. Texas A&M University; 2009. [cited 2021 Jan 19].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-3039.
Council of Science Editors:
Anisimov PM. Quantum coherence phenomena in x-ray optics. [Doctoral Dissertation]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-3039
Texas A&M University
4.
Novikova, Irina Borisovna.
Nonlinear magneto-optic effects in optically dense Rb vapor.
Degree: PhD, Physics, 2004, Texas A&M University
URL: http://hdl.handle.net/1969.1/364
► Nonlinear magneto-optical effects, originated from atomic coherence, are studied both theoretically and experimentally in thermal Rb vapor. The analytical description of the fundamental properties of…
(more)
▼ Nonlinear magneto-optical effects, originated from atomic coherence, are studied both theoretically and experimentally in thermal Rb vapor. The analytical description of the fundamental properties of coherent media are based on the simplified three- and four-level systems, and then verified using numerical simulations and experimental measurements. In particular, we analyze the modification of the long-lived atomic coherence due to various physical effects, such as reabsorption of
spontaneous radiation, collisions with a buffer gas atoms, etc. We also discuss the importance of the high-order nonlinearities in the description of the polarization rotation for the elliptically polarized light. The effect of self-rotation of the elliptical polarization is also analyzed.
Practical applications of nonlinear magneto-optical effects are considered in precision metrology and magnetometery, and for the generation of non-classical states of electromagnetic field.
Advisors/Committee Members: Welch, George R. (advisor), Scully, Marlan O. (committee member), Hemmer, Phillip R. (committee member), Sokolov, Alexei V. (committee member).
Subjects/Keywords: quantum optics; nonlinear optics; coherent effects; magneto-optic effects
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APA ·
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MLA ·
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APA (6th Edition):
Novikova, I. B. (2004). Nonlinear magneto-optic effects in optically dense Rb vapor. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/364
Chicago Manual of Style (16th Edition):
Novikova, Irina Borisovna. “Nonlinear magneto-optic effects in optically dense Rb vapor.” 2004. Doctoral Dissertation, Texas A&M University. Accessed January 19, 2021.
http://hdl.handle.net/1969.1/364.
MLA Handbook (7th Edition):
Novikova, Irina Borisovna. “Nonlinear magneto-optic effects in optically dense Rb vapor.” 2004. Web. 19 Jan 2021.
Vancouver:
Novikova IB. Nonlinear magneto-optic effects in optically dense Rb vapor. [Internet] [Doctoral dissertation]. Texas A&M University; 2004. [cited 2021 Jan 19].
Available from: http://hdl.handle.net/1969.1/364.
Council of Science Editors:
Novikova IB. Nonlinear magneto-optic effects in optically dense Rb vapor. [Doctoral Dissertation]. Texas A&M University; 2004. Available from: http://hdl.handle.net/1969.1/364
. 
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