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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"Pump-probe spectroscopy"”.
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Photoinduced dynamics studied by ultrafast single-shot pump-probe spectroscopy
… on the development of dual-echelon single-shot spectroscopy and its applications to study irreversible photoinduced dynamics. First, the ultrafast laser sources and the related control and characterization techniques are discussed. In particular, we have invented a two-stage dual-beam …
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Femtosecond pump-probe spectroscopy of chemical reactions in liquids and crystals
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1998.
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Studying Ultrafast Vibrational dynamics of Intramolecular Hydrogen Bonds using Broadband Infrared Pump-Probe Spectroscopy.
… presents work done by using ultrafast Infrared pump-probe spectroscopy to study the vibrational dynamics of two intramolecular hydrogen bonded complexes, 10-Hydroxybenzo[h]quinolone (HBQ) and 2-(2′-Hydroxyphenyl)benzothiazole (HBT) dissolved in carbon tetrachloride. One of the biggest difficulty …
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Decoupling bulk- and surface-limited lifetimes in thin kerfless silicon wafers using spectrally resolved transient absorption pump-probe spectroscopy and computer simulations
… Herein, spectrally resolved transient absorption pump-probe spectroscopy and extensive Technology Computer Aided Design simulations are used to decouple the bulk- and surface-limited lifetimes of thin kerfless silicon wafers in a single measurement. A range of sample conditions are studied. It is …
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Experimental investigations of excited-state dynamics in conjugated polymers using time-resolved laser spectroscopy
In this thesis, time-resolved laser spectroscopy has been used to advance the understanding of the excited-state dynamics in a variety of conjugated polymers and related systems. The properties of electron-phonon coupling in the conjugated polymer ladder-type methyl-substituted poly(para-phenylene) …
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The Effects Of Noncovalent Interactions Studied By Ultrafast Two-Dimensional Infrared Spectroscopy
… ultrafast two-dimensional infrared (2DIR) spectroscopy and ultrafast polarization dependent mid-IR pump-probe spectroscopy. Bis(cyclopentadienyl ruthenium dicarbonyl) dimer and bis(cyclopentadienyl iron dicarbonyl) dimer are two fluxional metal carbonyl complexes that exist as multiple …
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Three dimensional vibrational spectroscopy and shock initiation of hmx
3D spectroscopy was employed to probe and visualize energy flows through molecules from excited parent states. Studies with IR-Raman pump probe spectroscopy show clearly that the characteristics of the vibrational relaxation pathway depend strongly upon the initial excited states. By employing 3D …
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Applications of pump-probe and two-photon techniques in time-resolved fluorescence miscroscopy and spectroscopy
Pump-probe spectroscopy has long been useful in the elucidating ultrafast molecular phenomena. We developed a variation of time-resolved, pump-probe methodology using cross-correlation principles of the frequency-domain. An unique feature of our technique is that the low-frequency, cross …
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Molecular Structure-nonlinear Optical Property Relationships For A Series Of Polymethine And Squaraine Molecules
… fluorescence and white-light continuum pump-probe spectroscopy) to obtain the 2PA spectra revealing 2PA bands, and we confirm the experimental data by comparing the results from the different methods mentioned. By systematically altering the structure of polyemthines and squaraines, we …
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Ultrafast spatiotemporal dynamics of photoexcitations in two-dimensional semiconductors
… transition metal dichalcogenides. Using pump-probe spectroscopy, and a range of steady state characterization techniques (ellipsometry, reflectance, photoluminescence), we study the formation and decay of excitons in these materials at low excitation densities. We find that the …
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Ultrafast Ultra-confined Plasmon Phonon Interactions
… and acoustic modes as a sensitive nanomechanical probe. Initially this coupling allows us to discover the NPoM “bouncing mode” by performing ultrafast pump- probe spectroscopy on single constructs. Thorough finite element method simulations allow us to create a simple analytical model relat- ing …
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Spectroscopic Studies of Charge Dynamics in Non-Fullerene Organic Solar Cells
… the model system P3TEA:SF-PDI$_2$ via pump-probe spectroscopy and time-resolved photoluminescence spectroscopy. We find ultrafast charge generation as well as regeneration of singlets via encounters of free electrons and holes. Additionally, we observe slow ($\sim$ 100 ps) and thermally …
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Time-Resolved Studies of Magnetic and Non-Magnetic Narrow-Gap Semiconductors
… and non-magnetic NGS using ultrafast-laser spectroscopy techniques such as pump-probe spectroscopy and magneto-optical Kerr/Faraday effect, are reported. Our samples include: InSb-based quantum wells with different confinement potentials; InMnSb films, the newest III-V ferromagnetic …
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Characterizing Ultrafast Equilibrium Dynamics Using Third-Order Nonlinear Mid-Infrared Spectroscopies
… were extracted from polarization-dependent pump probe spectroscopy and local environment dynamics surrounding a vibrational probe were detected using two-dimensional infrared spectroscopy.Effects of ligand structural variation on the ultrafast dynamics of a series of copper complexes were …
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High speed nonlinear optical components for next-generation optical communications
… next-generation optical networks. Time-resolved pump-probe spectroscopy using pulses with a pulse width of 3ps from mode-locked laser sources was utilized to accurately measure the carrier dynamics in the device(s) under test. The research work into four main topics: (a) a long SOA, (b) the …
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Ultrafast Charge and Energy transfer Dynamics in Organic-Transition Metal Dichalcogenides Heterostructures
… using helicity and time resolved ultrafast pump probe spectroscopy. A valley polarization of 0.2 and a lifetime of 19 ps in Pentacene/WSe2 heterostructure was observed. Excitation resonant to and above the optical gap of WSe2 leads to a 4-fold and 2 orders of magnitude difference in the …
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Photoinduced Dynamics Studied using Single-Shot Optical and Terahertz Spectroscopy
… single-shot optical and terahertz (THz) spectroscopy to study irreversible photoinduced dynamics and materials far from equilibrium. First, we motivate the understanding of photoinduced material responses as initiated by, and probed with, ultrafast laser pulses, including the techniques …
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Chemical Structure - Nonlinear Optical Property Relationships For A Series Of Two-photon Absorbing Fluorene Molecules
… were employed: two-photon fluorescence spectroscopy, white-light continuum pump-probe spectroscopy, and the Z-scan technique. In addition, full linear spectroscopic characterization was performed on these molecules along with supplementary quantum chemical calculations to obtain certain …
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Static and ultrafast optical properties of nanolayered composites : gold nanoparticles embedded in polyelectrolytes
… was determined experimentally by ultrafast pump-probe spectroscopy. This was achieved by simultaneous measurements of the changes in the reflectance and transmittance of the excited sample over a broad spectral range. The changes in the real and imaginary parts of the dielectric function …
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Ultrafast Investigations of Exciton Dynamics in 0D and 2D Hybrid Semiconductor Nanomaterials
… In this thesis, I utilize ultrafast pump-probe spectroscopy to study the fundamental properties of hybrid semiconductor nanomaterials. This technique allows the electronic and vibrational dynamics of these materials to be investigated with femtosecond time resolution, providing new …
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