Дисертації з теми "Coherent spectroscopy"
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Beaman, R. A. "Two beam coherent spectroscopy." Thesis, Cardiff University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379609.
Повний текст джерелаQuilter, John Howard. "Coherent spectroscopy of single quantum dots." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/7711/.
Повний текст джерелаViranna, Narendra Balaguru. "Coherent anti-Stokes Raman spectroscopy of diamond." Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/26229.
Повний текст джерелаKirkbride, James M. R. "Coherent transient spectroscopy with quantum cascade lasers." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:c7b897e5-052f-4c15-a3c9-f95ca3b56d70.
Повний текст джерелаTurner, Daniel Burton. "Investigating exciton correlations using coherent multidimensional optical spectroscopy." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62037.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Vita. Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 153-166).
The optical measurements described in this thesis reveal interactions among bound electron-hole pairs known as excitons in a semiconductor nanostructure. Excitons are quasiparticles that can form when light is absorbed by a semiconductor. Exciton interactions gained prominence in the 1980s when unexpected signals were observed in studies of carrier dynamics. The presence of exciton interactions in semiconductors motivated an ongoing, focused research effort not only because the materials had valuable commercial applications but also because the interactions could be used to test fundamental theories of many-body physics. Laser light provides a coherent electric field with a well defined phase. In linear spectroscopy, an electric field that is resonant with an exciton transition will induce coherent oscillations of electronic charge density. The charges will oscillate at the transition frequency with a well defined phase, and these oscillations will radiate a signal that has an amplitude proportional to the incident field amplitude and has the same direction as the incident light. If the laser light is intense, its field may induce a high density of excitons, and the field can interact with those excitons to induce transitions to higher-energy states composed of multiple interacting excitons. Many-body interactions among the excitons can predictably modify--or unpredictably scramble--the quantum phase of the exciton. The interactions can produce signals that have amplitudes proportional to high powers of the incident field amplitude, and the signal fields often propagate in directions different than the incident field. The signal fields contain information--often encoded in their phases--that can reveal the nature of the higher-energy states and the many-body interactions that produced them. Thus, many-body interaction studies rely on measurements of exciton phases that are reflected in the optical phases of coherent signals. These measurements require a tool that can detect optical coherence before the exciton phases are scrambled by the environment. Coherent ultrafast optical spectroscopy is that tool. The spectra displayed in this work were measured by an experimental apparatus that separates the electric fields as needed into different laser beams with controllable directions; it controls the optical phase, arrival time, and polarization of the femtosecond light pulse(s) in each of those beams; it then recombines all of the beams at the 5 sample to generate the signal field; and finally it measures the signal field, including its phase. Using this instrument, we isolated--with a high degree of selectivity--signals that arose from different numbers of field interactions and from different microscopic origins using various beam geometries and pulse timing sequences. In this thesis, we present electronic spectra measured at varying orders in the electric field to isolate and measure the properties of excitons and their many-body interactions. As the number of electric fields is increased and the resulting higherorder signals are generated, interactions involving increasing numbers of particles can be measured. The vast majority of previous work focused on the interactions manifest in third-order signals. This thesis not only includes new insights gained from third-order signals, but also includes new phenomena observed in fifth-order and seventh-order signals. We measure signals due to four-particle correlations in the form of bound biexcitons and unbound-but-correlated exciton pairs. We also measure signals due to six-particle correlations in the form of bound triexcitons. Although we searched for them, there were no signals due to eight-particle correlations, indicating that the set of multiexciton states truncates. We thus measured the properties and the extent of many-body interactions in this system. The spectra presented here reveal a large set of excitonic many-body interactions in GaAs quantum wells and answer questions about the many-body interactions posed decades ago. The optical apparatus constructed to perform these measurements will soon be used to measure correlations in a range of systems, including other semiconductors and their nanostructures, molecular aggregates, molecules, and photosynthetic complexes. Because future technologies such as entangled photon sources, advanced photovoltaics, and quantum information processing will rely on these types of materials and their many-body correlations, it is important to develop techniques to measure their microscopic interactions directly.
by Daniel Burton Turner.
Ph.D.
Somma, Carmine. "Coherent Multidimensional Off-resonant THz Spectroscopy on Semiconductors." Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18512.
Повний текст джерелаFor the first time, the coherent generation of ultrashort MV/cm field pulses with a spectrum covering the frequency range 0.1-30 THz is demonstrated in the organic crystal DSTMS. Coherent multidimensional terahertz spectroscopy (CMTS) has become a prominent technique for, e.g., driving low-energy excitations in semiconductors and monitoring their coherent dynamics. A novel CMTS technique using three phase-locked inter-delayed THz pulses is implemented. It relies on a collinear interaction of the pulses with a sample, so that different contributions to the nonlinear signal are emitted in the same direction, and thus can be measured all at once. Phase-resolved detection by electro-optic sampling allows for measuring amplitude and absolute phase of the nonlinear signal, thereby enabling to investigate the evolution of coherent interactions between quantum excitations in real time. In CMTS, the nonlinear signal is dissected into the distinct nonlinear contributions in the corresponding multidimensional frequency domain. This novel technique is applied to study the nonlinear off-resonant response of two undoped bulk semiconductors, the wide-bandgap ferroelectric lithium niobate (LiNbO3) and the narrow-bandgap indium antimonide (InSb). In LiNbO3, the nonlinear signal is generated by a femtosecond nonlinear shift current (SC), a distinctive characteristic of the bulk photovoltaic effect. The SC stems from the lack of inversion symmetry and the ultrafast dephasing of the field-induced interband coherent polarization due to a sufficiently high decoherence rate, which enables tunneling of electrons from the valence to the conduction band. In InSb, the nonlinear signal is caused by the coherent response on both the two-phonon and two-photon interband excitations. The impulsive generation of the two-phonon coherent polarization is enhanced by the large interband transition dipole of InSb, resulting in much larger polarization amplitudes than in the regime of linear response.
Branderhorst, Matthijs Pieter Arie. "Coherent control of decoherence." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670035.
Повний текст джерелаJerebtsov, Serguei Nikolaevich. "Femtosecond time-resolved spectroscopy of coherent oscillations in nanomaterials." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1358.
Повний текст джерелаArlt, Sebastian. "Coherent femtosecond spectroscopy of exciton-continuum interaction in semiconductors /." Zürich, 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13475.
Повний текст джерелаStowe, Matthew C. "Direct frequency comb spectroscopy and high-resolution coherent control." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3315768.
Повний текст джерелаDobrev, Georgi. "Laser spectroscopy for coherent manipulation and state-specific probing of atoms and molecules." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1083/document.
Повний текст джерелаThis thesis describes experimental work on different techniques aiming to achieve control of the quantum state of atoms and molecules, envisaging applications in quantum computing, metrology and astrophysics.Successful coherent control requires careful design of operating conditions for a system where decoherence is minimized. The construction of a calcium atomic beam is presented as a necessary element in experiments with laser excitation schemes chosen to provide high-fidelity preparation of a quantum satate by means of composite pulses. The second section describes my contribution to the improvement of the relative frequency stability of the Cs fountain clock CSF2 at the German institute of metrology. A modified magneto-optical trap is employed to form a beam of slow cesium atoms. They are prepared in a specific dark state and subsequently are efficiently transferred to the optical molasses of the fountain. Increasing number of atoms participating in the clock cycle in this way improves the stability of the clock by a factor of 6.The third section is concerned with spectra of metal hydride molecules NiH and FeH. Several sources for production of these molecules in laboratories were developed and tested. A differential laser absorption experiment and a cavity-enhanced spectroscopy technique are applied on the w??kly absorbing NiH molecules, to obtain absorption coefficients for the red bands of NiH. The Zeeman response of the FeH molecule (a probe for magnetic fields in cool stars) in the near-IR is investigated by precision laser spectroscopy establishing Landé factors for 33 rovibrational levels of the F 4? electronic state
Demirdöven, Nurettin 1974. "Coherent two-dimensional infrared spectroscopy : a study of coupled vibrations." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/17653.
Повний текст джерелаVita.
Includes bibliographical references.
This thesis provides an introduction to experimental techniques used in two-dimensional (2D) infrared (IR) spectroscopy, outlines how third-order nonlinear response of a multi-level vibrational system is calculated, and provides a detailed methodology of line shape analysis in 2D spectroscopy. Specific emphasis is given to inherent sensitivity of 2D spectroscopy to correlated spectral broadening. The signatures of highly correlated transition energy fluctuations in a model system of two strongly coupled carbonyl stretching vibrations are reflected by the elongation of the cross peaks along the diagonal of the 2D spectrum. The dynamics of this correlation is monitored by the changes in the 2D line shapes and successfully modeled using a correlated spectral diffusion model. The sensitivity of 2D IR spectroscopy to interactions between multiple vibrational coordinates is also explored in conformationally complex polypeptides and proteins with well-defined secondary structures. 2D IR spectroscopy of β-hairpins and globular proteins with antiparallel (AP) β-sheet domains is studied to identify 2D markers of AP β-sheet conformation. The experiments on β-hairpins and proteins with varying percentage of β-sheet character showed that the formation of cross peaks between the two characteristic vibrational modes of AP β-sheets is a marker of AP β-sheet secondary structure. The intensity, location and line shapes of the cross peaks are qualitatively related to the size, geometry and the conformational variations in the AP β-sheet structure.
by Nurettin Demirdöven.
Ph.D.
Mahmood, Fahad Ph D. Massachusetts Institute of Technology. "Femtosecond spectroscopy of coherent phenomena in quantum materials : a dissertation." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104461.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 217-236).
Quantum materials are solids that cannot be described by the single-particle band models of conventional condensed matter physics. Rather strong inter-particle interactions and coupling between various degrees of freedom (charge, spin, orbital and lattice) lead to emergent phases such as high-temperature superconductivity, spin and charge density wave ordering and topologically protected 2D Dirac fermions. In the time-resolved experiments in this work, an initial laser 'pump' pulse drives the sample out-of-equilibrium by manipulating the electronic band structure, generating quasi-particles and/or exciting specific collective modes. The resulting dynamic changes are then tracked as a function of time by using two different spectroscopic tools: transient reflectivity and time and angle resolved photoemission (Tr-ARPES). One approach is to perturb the system gently (low pump intensity) to preserve the underlying order. Transient reflectivity experiments are done in this weak perturbation regime to study the following phenomena: (1) Collective excitations (amplitude and phase mode) of the fluctuating charge density wave order in the cuprate superconductor La₂-xSrxCuO₄; (2) Decay dynamics of valley polarized excitons in the monolayer transition metal dichalcogenide MoSe₂; and (3) a confinement-deconfinement transition of single-particle excitations in the spin-orbit assisted Mott insulator Na₂IrO₃. In the opposite regime (strong perturbation), it is possible to drive electronic materials into non-equilibrium phases with fundamentally different properties than in equilibrium. This work uses mid-IR pump pulses to directly couple photons to an electronic system to create hybrid electron-photon states. In this case, the oscillating electric field of the pump causes Dirac fermions to experience a time-periodic potential to generate Floquet-Bloch states which repeat in both energy and momentum. These and other similar photo-induced states are observed and characterized using Tr-ARPES on the topological insulators Bi₂Se₃ and Bi₂Te₃.
by Fahad Mahmood.
Ph. D.
Poulin, Peter Roland 1973. "Coherent lattice and molecular dynamics in ultrafast single-shot spectroscopy." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32430.
Повний текст джерелаIncludes bibliographical references.
This thesis focuses on the development, refinement, and application of dual- echelon single-shot ultrafast spectroscopy to the study of coherent nuclear motion in condensed phase systems. The general principles of the single-shot method are described, and particular emphasis is given to the general applicability and shortcomings of this technique and the extraction of data from raw laboratory images. Coupled to the single-shot system is a synchronously pumped dual-beam noncollinear optical parametric amplifier which was developed to provide independently tunable pump and probe beams in the visible and UV regions of the electromagnetic spectrum. The second part of the thesis concerns the application of this technique to the study of atomic motions in liquids and solids. Single-shot nonresonant impulsive stimulated Raman scattering (ISRS) measurements in m-iodoanisole and bismuth germanate reveal the existence of transient coherent behavior. High-field resonant excitation of the semimetals bismuth, antimony and tellurium, as well as the semiconductor germanium telluride, reveals dramatic lattice anharmoniticity as a function of pump fluence. Finally, ultrafast photodissociation of the triiodide ion both in solution and in the solid state gives considerable insight regarding the role of the local environment in mediating chemical reaction dynamics.
by Peter Roland Poulin.
Ph.D.
Brunner, Daniel. "Laser spectroscopy of coherent quantum states in single quantum dots." Thesis, Heriot-Watt University, 2010. http://hdl.handle.net/10399/2350.
Повний текст джерелаPayne, Lukas M. "Optical extinction and coherent multiphoton micro-spectroscopy of single nanoparticles." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/87182/.
Повний текст джерелаBurkart, Johannes. "Optical feedback frequency-stabilized cavity ring-down spectroscopy - Highly coherent near-infrared laser sources and metrological applications in molecular absorption spectroscopy." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY045/document.
Повний текст джерелаHigh-precision molecular absorption spectroscopy is a powerful tool for fundamental physics and metrology, as well as for a broad range of applications in fields such as environmental sciences, planetology and astrophysics. In recent years, spectroscopic techniques based on the enhanced interaction of laser light with molecular samples in high-finesse optical cavities have provided outstanding detection sensitivities on the absorption axis, while the spectrometer frequency axis rarely met as high precision standards.In this thesis, we addressed this challenge by the development of Optical Feedback Frequency-Stabilized Cavity Ring-Down Spectroscopy (OFFS-CRDS). This novel technique features a unique combination of sub-kHz frequency resolution and stability, kW/cm^2-level intracavity light intensity, a shot-noise limited absorption detectivity down to 2 x 10^(−13) cm^(−1)Hz^(-1/2), as well as a detection limit of 8.4 x 10^(−14) cm^(−1) on a narrow spectral interval. This unprecedented performance is based on the tight Pound-Drever-Hall lock of the ring-down cavity to a single-sideband-tuned distributed-feedback diode laser which is optical-feedback-stabilized to a highly stable V-shaped reference cavity. To transfer the coherence of this sub-kHz laser source to noisier lasers in other spectral regions through an optical frequency comb, we have explored a novel high-bandwidth feed-forward phase cloning scheme and demonstrated a residual phase error as low as 113 mrad. Applying OFFS-CRDS to the spectroscopy of CO_2 near 1.6 μm, we obtained a broadband spectrum with a dynamic range of 8 x 10^5 and retrieved twelve absolute transition frequencies with kHz-accuracy by measuring sub-Doppler saturated absorption Lamb dips with a comb-assisted setup. Furthermore, we have performed a comprehensive analysis of systematic error sources in CRDS and derived an analytic formula for the non-exponential ring-down signal in a weakly saturated regime, which may contribute towards future concentration-independent transition dipole moment measurements. Our results open up promising perspectives for metrological applications of OFFS-CRDS, such as advanced absorption lineshape studies, isotopic ratio measurements and extensive saturated absorption spectroscopy in the near infrared
Hettich, Mike [Verfasser]. "Investigation of Multilayer Systems by Coherent Acoustic Phonon Spectroscopy / Mike Hettich." München : Verlag Dr. Hut, 2014. http://d-nb.info/1055863508/34.
Повний текст джерелаPestov, Dmitry Sergeyevich. "Detection of bacterial endospores by means of ultrafast coherent raman spectroscopy." Texas A&M University, 2008. http://hdl.handle.net/1969.1/85958.
Повний текст джерелаMarian, Adela Ye Jun. "Direct frequency comb spectroscopy for optical frequency metrology and coherent interactions." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/dissertations/fullcit/3186934.
Повний текст джерелаBeaudoin, Bertrand Julien. "Homodyne High-harmonic Spectroscopy: Coherent Imaging of a Unimolecular Chemical Reaction." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23173.
Повний текст джерелаStrüber, Christian [Verfasser]. "Ultrafast coherent control and multidimensional spectroscopy on the nanoscale / Christian Strüber." Bielefeld : Universitätsbibliothek Bielefeld, 2014. http://d-nb.info/1048176096/34.
Повний текст джерелаWituschek, Andreas [Verfasser], and Frank [Akademischer Betreuer] Stienkemeier. "Phase-modulated coherent time-domain spectroscopy in the extreme ultraviolet regime." Freiburg : Universität, 2020. http://d-nb.info/1226657095/34.
Повний текст джерелаPorter, Fiona M. "A study of temperature measurement using Coherent Anti-Stokes Raman Spectroscopy." Thesis, University of Surrey, 1985. http://epubs.surrey.ac.uk/847913/.
Повний текст джерелаLiebel, Matz. "Understanding molecular dynamics with coherent vibrational spectroscopy in the time-domain." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:e0289d80-f6e3-4e6f-817e-f8dd55d15bc4.
Повний текст джерелаSmith, Lowenna. "Magneto-optical spectroscopy and coherent Raman studies of dilute magnetic semiconductors." Thesis, University of Bath, 2007. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439273.
Повний текст джерелаTenorio-Pearl, Jaime Oscar. "Coherent control of a trapped electron in a disordered dielectric." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708428.
Повний текст джерелаXu, Xiaoji. "New methods of coherent anti-Stokes Raman spectroscopy based on broadband pulses." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/8445.
Повний текст джерелаLee, Martin. "Imaging intra-cellular wear debris with coherent anti-Stokes Raman scattering spectroscopy." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7735.
Повний текст джерелаBarlow, Aaron M. "Spectral Distortions & Enhancements In Coherent Anti-Stokes Raman Scattering Hyperspectroscopy." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32388.
Повний текст джерелаCamp, Charles Henry Jr. "Label-free flow cytometry using multiplex coherent anti-Stokes Raman scattering (MCARS) spectroscopy." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42733.
Повний текст джерелаGause, Oliver [Verfasser]. "Femtosecond spectroscopy and coherent control on flavins in the gas phase / Oliver Gause." Berlin : Freie Universität Berlin, 2012. http://d-nb.info/1027151558/34.
Повний текст джерелаGierakowski, Lays Rezende Valim. "Coherent multidimensional infrared spectroscopy : application to the study of biomolecules under oxidative stress." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/62631.
Повний текст джерелаVaughan, Joshua Charles. "Two-dimensional ultrafast pulse shaping and its application to coherent control and spectroscopy." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32492.
Повний текст джерелаVita.
Includes bibliographical references (p. 167-182).
This thesis develops powerful new methods for shaping femtosecond laser pulses in two dimensions and explores their application to coherent control of propagating lattice excitations and degenerate four-wave mixing spectroscopy. Pulse shaping in two dimensions is achieved by manipulating the spectral components of ultrashort laser pulses within many horizontal slices of the pulse. Each horizontal slice is independently shaped by means of a two-dimensional liquid crystal spatial light modulator, and taken together the shaped regions form sophisticated optical waveforms with time-dependent spatial profiles. Automated optical control over coherent lattice responses that are both time- and position-dependent across macroscopic length scales is demonstrated. Two- dimensional (2D) femtosecond pulse shaping was used to generate excitation light fields that were directed toward distinct regions of crystalline samples, producing terahertz-frequency lattice vibrational waves that emanated outward from their multiple origins at lightlike speeds. Interferences among the waves resulted in fully specified far-field responses, including tilted, focusing, or amplified wavefronts. Generation and coherent amplification of terahertz travelling waves and terahertz phased-array generation are also demonstrated. A novel approach to coherent nonlinear optical spectroscopy based on 2D femtosecond pulse shaping is introduced. Multiple phase-stable output beams are created and overlapped at the sample in a phase-matched boxcars geometry via 2D femtosecond pulse shaping.
(cont.) The pulse timing, shape, phase, and spectral content within all beams may be specified, yielding an unprecedented level of control over the interacting fields in nonlinear spectroscopic experiments. Heterodyne detection and phase cycling of the nonlinear signal is easily implemented due to the excellent phase stability between each output beam. This approach combines the waveform generation capabilities of magnetic resonance spectroscopy with the wavevector specification and phase-matching of nonlinear optical spectroscopy, yielding the signal selectivity and control capabilities of both. Results on three prototype systems will be used to illustrate the exciting possibilities with this method.
by Joshua Charles Vaughan.
Ph.D.
Michan, Juan Mario. "Implementation of a coherent Lyman-alpha source for laser cooling and spectroscopy of antihydrogen." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46605.
Повний текст джерелаKhalil, Munira 1975. "A tale of coupled vibrations in solution told by coherent two-dimensional infrared spectroscopy." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/16607.
Повний текст джерелаVita.
Includes bibliographical references.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Coherent two-dimensional infrared (2D IR) spectroscopy is used as a tool for investigating the molecular structure and dynamics of coupled vibrations in solution on a picosecond timescale. The strongly coupled asymmetric and symmetric carbonyl stretches of Rh(CO)₂C₅H₇0₂ (RDC) dissolved in hexane serve as a convenient model system. Fourier transform 2D IR spectra are obtained from heterodyne-detected third-order nonlinear signals using a sequence of broad bandwidth femtosecond IR pulses. A 2D IR correlation spectrum with absorptive lineshapes results from the addition of 2D rephasing and non-rephasing spectra, which sample conjugate frequencies in the evolution time period. The 2D IR correlation spectrum contains peaks with different positions, signs, amplitudes and lineshapes. The positions of the peaks map the transition frequencies between the ground, singly, and doubly excited states of the system, and thus describe the anharmonic vibrational potential. Peak amplitudes reflect the relative magnitudes and orientations of the transition dipole moments in the molecular frame, the electrical anharmonicity of the system, and the vibrational relaxation dynamics. The 2D line shapes are sensitive to the complicated system-bath interactions in solution. 2D IR spectra taken with varying polarization conditions and as a function of a variable waiting time can be used to isolate and quantify these spectroscopic observables. The polarization-selective 2D IR spectra of RDC in hexane are analyzed in terms of two coupled local coordinates to obtain their mutual orientation and the magnitude of the coupling between them. Evidence of vibrational coherence transfer between close-lying transition frequencies is indicated by the presence of extra induced peaks in 2D IR
(cont.) rephasing spectra. The data is modeled by using Redfield theory to account for coherence transfer, vibrational dephasing and population relaxation in a multilevel vibrational system. Building on the studies of the RDC model system, 2D IR spectroscopy is used to study the thermal denaturation of RNase A by characterizing the temperature-dependent Amide I band. A nonlinear IR probe is used to study the early events in the laser temperature-jump initiated denaturation of RNase A.
by Munira Khalil.
Ph.D.
Stone, Katherine Walowicz. "Coherent multi-exciton dynamics in semiconductor nanostructures via two-dimensional Fourier transform optical spectroscopy." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/49554.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 139-149).
The Coulomb correlations between photoexcited charged particles in materials such as photosynthetic complexes, conjugated polymer systems, J-aggregates, and bulk or nanostructured semiconductors produce a hierarchy of collective electronic excitations (i.e. excitons, biexcitons, etc.) which may be harnessed for applications in quantum optics, light-harvesting, or quantum information technologies. These excitations represent correlations among successively greater numbers of electrons and holes, and their associated multiple-quantum coherences could reveal detailed information about complex many-body interactions and dynamics. However, unlike single-quantum coherences involving excitons, multiple-quantum coherences do not radiate and they have largely eluded direct observation and characterization. In this work, I present a novel optical technique, two-quantum two-dimensional Fourier transform optical spectroscopy, which allows direct observation of the dynamics of multiple-exciton states that reflect the correlations of their constituent electrons and holes. The approach is based on closely analogous methods in nuclear magnetic resonance, in which multiple phase-coherent fields are used to drive successive transitions such that multiple-quantum coherences can be accessed and probed. A spatiotemporal femtosecond pulse shaping technique has been used to overcome the challenge of control over multiple, noncollinear phase-coherent optical Fields in the experimental geometries that are used to isolate selected signal contributions through wavevector matching.
(cont.) Results from a GaAs quantum well system reveal distinct coherences of biexcitons that are formed from two identical excitons or from two excitons whose holes are in di®erent spin sublevels ("heavy-hole" and "light-hole" excitons). The biexciton binding energies and dephasing dynamics are determined, and changes in the dephasing rates as a function of the excitation density are observed, revealing still higher-order correlations due to exciton-biexciton interactions. Two-quantum coherences due to four-particle correlations that do not involve bound biexciton states but that in°uence the exciton properties are also observed and characterized. I also present one-quantum two-dimensional Fourier transform optical spectroscopy measurements which show that the higher-order correlations isolated by two-quantum techniques are highly convolved with two-particle correlations in the conventional one-quantum measurements.
by Katherine Walowicz Stone.
Ph.D.
Upadhya, Prasanth Chandrashekara. "Coherent generation and detection of Terahertz radiation : time domain Terahertz spectroscopy of molecular crystals." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614771.
Повний текст джерелаTumino, Biagio. "Growth and coherent spectroscopy of europium- and praseodymium-doped crystals for quantum memory applications." Paris 6, 2013. http://www.theses.fr/2013PA066188.
Повний текст джерелаRare-earth-doped solids are promising materials as light-matter interfaces for quantum applications. In particular, europium-doped yttrium orthosilicate crystal (Eu3+:Y2SiO5) shows coherence properties and a ground-state energy-level structure suitable for quantum memory applications. Within the european project QuRep, spectroscopic investigations of this material are reported in order to determine the optimal conditions (in terms of material’s purity or ions concentration) for obtaining high performance quantum memories. Two crystal growth techniques (Czochralski and melting zone) are also used in order to refine the growth conditions for this material. The europium optical transition 7F0 – 5D0 is investigated by high resolution-absorption and photon echo techniques in order to study the absorption coefficient peak, the inhomogeneous linewidth and the optical coherence lifetime as function of different conditions. The hyperfine structure of the two europium isotopes (151Eu and 153Eu) is also analyzed by applying an external static magnetic field. Coherent Raman Scattering measurements are performed in order to measure the hyperfine coherence lifetime in 151/153Eu3+:Y2SiO5 found to be in the range of 10-20 ms at zero magnetic field
Hung, Yi-chen Hung. "Characterization of Nonequilibrium Reacting Molecular Plasmas and Flames using Coherent Anti-Stokes Raman Spectroscopy." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531930166735281.
Повний текст джерелаPaul, Jagannath. "Coherent Response of Two Dimensional Electron Gas probed by Two Dimensional Fourier Transform Spectroscopy." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6738.
Повний текст джерелаWijekoon, Wijekoon Mudiyanselage Kapila Piyasena. "Waveguide Surface Coherent anti-Stokes Raman Scattering Spectroscopy and optical second harmonic generation spectroscopy of molecules adsorbed on metal oxide surfaces." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184444.
Повний текст джерелаFeng, Zhenxing 1982. "Experimental and theoretical investigation of the coherent x-ray propagation and diffraction." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101122.
Повний текст джерелаHogben, Hannah J. "Coherent spin dynamics of radical pairs in weak magnetic fields." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:61c4ab7e-406f-4193-949a-b5a70f43e3e1.
Повний текст джерелаAtherton, Kathryn Jane. "Coherent Raman studies of optical nonlinearities in conjugated molecules and polymers." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298790.
Повний текст джерелаBinz, Marcel [Verfasser], and Frank [Akademischer Betreuer] Stienkemeier. "Phase-modulated coherent spectroscopy of rubidium: High-intensity effects and the interaction with helium nanodroplets." Freiburg : Universität, 2021. http://d-nb.info/1235325806/34.
Повний текст джерелаHensen, Matthias [Verfasser]. "Concentrating Light: Nano-devices for spectroscopy, ultra-fast current injection and coherent energy transport / Matthias Hensen." Bielefeld : Universitätsbibliothek Bielefeld, 2016. http://d-nb.info/1105645533/34.
Повний текст джерелаDey, Prasenjit. "Exciton Dynamics and Many Body Interactions in Layered Semiconducting Materials Revealed with Non-linear Coherent Spectroscopy." Thesis, University of South Florida, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10076073.
Повний текст джерелаAtomically thin, semiconducting transition metal dichalogenides (TMDs), a special class of layered semiconductors, that can be shaped as a perfect two dimensional material, have garnered a lot of attention owing to their fascinating electronic properties which are achievable at the extreme nanoscale. In contrast to graphene, the most celebrated two-dimensional (2D) material thus far; TMDs exhibit a direct band gap in the monolayer regime. The presence of a non-zero bandgap along with the broken inversion symmetry in the monolayer limit brands semiconducting TMDs as the perfect candidate for future optoelectronic and valleytronics-based device application. These remarkable discoveries demand exploration of different materials that possess similar properties alike TMDs. Recently, III-VI layered semiconducting materials (example: InSe, GaSe etc.) have also emerged as potential materials for optical device based applications as, similar to TMDs, they can be shaped into a perfect two-dimensional form as well as possess a sizable band gap in their nano-regime. The perfect 2D character in layered materials cause enhancement of strong Coulomb interaction. As a result, excitons, a coulomb bound quasiparticle made of electron-hole pair, dominate the optical properties near the bandgap. The basis of development for future optoelectronic-based devices requires accurate characterization of the essential properties of excitons. Two fundamental parameters that characterize the quantum dynamics of excitons are: a) the dephasing rate, γ, which represents the coherence loss due to the interaction of the excitons with their environment (for example- phonons, impurities, other excitons, etc.) and b) excited state population decay rate arising from radiative and non-radiative relaxation processes. The dephasing rate is representative of the time scale over which excitons can be coherently manipulated, therefore accurately probing the source of exciton decoherence is crucial for understanding the basic unexplored science as well as creating technological developments. The dephasing dynamics in semiconductors typically occur in the picosecond to femtosecond timescale, thus the use of ultrafast laser spectroscopy is a potential route to probe such excitonic responses.
The focus of this dissertation is two-fold: firstly, to develop the necessary instrumentation to accurately probe the aforementioned parameters and secondly, to explore the quantum dynamics and the underlying many-body interactions in different layered semiconducting materials. A custom-built multidimensional optical non-linear spectrometer was developed in order to perform two-dimensional spectroscopic (2DFT) measurements. The advantages of this technique are multifaceted compared to regular one-dimensional and non-linear incoherent techniques. 2DFT technique is based on an enhanced version of Four wave mixing experiments. This powerful tool is capable of identifying the resonant coupling, probing the coherent pathways, unambiguously extracting the homogeneous linewidth in the presence of inhomogeneity and decomposing a complex spectra into real and imaginary parts. It is not possible to uncover such crucial features by employing one dimensional non-linear technique.
Monolayers as well as bulk TMDs and group III-VI bulk layered materials are explored in this dissertation. The exciton quantum dynamics is explored with three pulse four-wave mixing whereas the phase sensitive measurements are obtained by employing two-dimensional Fourier transform spectroscopy. Temperature and excitation density dependent 2DFT experiments unfold the information associated with the many-body interactions in the layered semiconducting samples.
Simon, Russell James. "The use of Coherent Anti-Stokes Raman Spectroscopy as a diagnostic technique for studying the hydrogenation of carbon moxide {i.e. monoxide} in a tube-wall reactor." Thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/23441.
Повний текст джерелаKarthik, G. "Investigations Of Spin-Dynamics And Steady-States Under Coherent And Relaxation Processes In Nuclear Magnetic Resonance Spectroscopy." Thesis, Indian Institute of Science, 2001. http://hdl.handle.net/2005/259.
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