Global ETD Search
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 67 for “"optical excitation"”.
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Remote optical excitation and sensing of structural vibration
… is concerned with non-contact techniques for optical excitation of mechanical vibrations in structures and with the use of non-contact fibre optic interferometers for the measurement of parameters which characterise these mechanical vibrations. Taken together, the excitation and sensing …
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Optical excitation of bulk semiconductors by phase-locked pulses.
Optical excitation of bulk semiconductors by phase-locked pulses.
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Optical Excitation of Metastable Krypton and Photoassociative Spectroscopy of Ultracold RbAr
… bodies of work. In the first, we investigate all-optical excitation methods to produce metastable-state krypton. The high energies required to excite rare gases out of their ground state present a unique challenge in the context of laser experiments. Laser physics work with rare gases often relies …
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BLUE-SHIFT OF EFFECTIVE BAND-GAP IN N-I-P-I DOPING SUPERLATTICES AS A FUNCTION OF OPTICAL EXCITATION INTENSITY
… of their electronic structure by external excitation, either optical or electrical. It has been routinely reported that the effective band-gap of a n-i-p-i doping superlattice undergoes a blue-shift when the intensity of the external excitation light (pump) is increased. In other words, the …
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Independent two-color optogenetic excitation of neural populations
The optical modulation of neurons with channelrhodopsins, a class of genetically encoded light-gated ion channels, has enabled the spatiotemporally precise interrogation of the roles individual cell types play in neural circuit dynamics. A topic of great interest to the neuroscience community is …
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Modal analysis of laser vibrated structures
… surface damage. This work extends current optical excitation techniques by demonstrating that a single laser pulse, with a power density below the surface ablation threshold, can also efficiently induce flexural vibration in a structure.
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Nanoscale Enhancement of Photosensitized Radionuclide Stimulated Therapy
… of reactive oxygen species (ROS) from the optical excitation of a photosensitizer (PS). Furthermore, this mechanism is highly immune stimulating, providing systemic tumor immunity with a reduction in metastasis. However, these materials had previously been limited by their dependence upon …
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The application of GHz bandwidth electrical pulses to a single semiconductor quantum dot.
… within a chargetunable heterostructure can be optically isolated using confocal microscopy, and electrically manipulated using an applied voltage. This thesis presents progress towards full opto-electrical control over a single dot, with a specific interest in the creation of a fully …
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Electronic excitation and atomic forces in optically excited group V semimetals
… of this work is to investigate how electronic excitation changes the forces between atoms in materials, causing large amplitude collective atomic motion, referred to as coherent phonon motion. The recent development of ultrafast optical spectroscopy has greatly advanced our understanding of …
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Structure-property relationships of dyes as applied to dye-sensitized solar cells
… impedance spectroscopy are employed to study optical and electrochemical properties of dye molecules. Computational methods, including density functional theory and time-dependent density functional theory, are used to validate and predict the optical and electronic properties of dye …
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Trapping, laser cooling, and spectroscopy of Thorium IV
Application of precision laser spectroscopy and optical clock technology to the ground and metastable, first excited state of the ²²⁹Th nucleus at < 10 eV has significant potential for use in optical frequency metrology and tests of variation of fundamental constants. This work is a report on the …
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Computational Techniques for Advancing Photoacoustic Microscopy
… (PAM), a hybrid modality that combines optical excitation and ultrasonic detection, has attracted considerable attention in basic and translational research. PAM not only enables in vivo label-free vascular imaging at the microscopic level, but also facilitates the assessment of …
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The effect of proton bombardment on semiconductor saturable absorber structure
… lifetimes by as much as a factor of 40 at low optical excitation densities. For high fluences, significant induced absorption was observed. The recovery of this excited state absorption did not show as significant a dependence on the level of proton bombardment. It is possible that the cause of …
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On the feasibility and application of optical p to n inversion
… inversion of a properly doped crystal via optical excitation is studied. This process involves a host substrate doped with deep donors for n-type light characteristic and compensated by a shallow acceptor for p-type characteristic in the dark. This substrate is analyzed using well-known …
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Studies of non-diffusive heat conduction through spatially periodic and time-harmonic thermal excitations
… spatially periodic and time-harmonic thermal excitations as a means for probing the non-diffusive transport regime, where the Fourier heat diffusion law breaks down. Boltzmann transport equation calculations of one-dimensional (1D) spatially sinusoidal thermal excitations are performed for …
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Optically-Assisted Scanning Tunneling Microscopy
… on the atomic level. With the addition of optical excitation, STM promises to become a powerful technique for single molecule spectroscopy, enabling one to examine the response of single molecules on a surface. Atomic scale laser-assisted STM has thus far remained an elusive goal, with few …
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Interfacing spin-based quantum sensors with complex systems
… diamond crystals that enable quantum sensing via optically active spin ground states. They have demonstrated high sensitivity in thermometry and magnetometry, reaching a temperature precision of 5mK/√Hz and magnetic field sensitivity of a single nuclear spin. Due to their nanometer size and …
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Photon-assisted spectroscopy of electronic interface states in perovskite oxide heterostructures
… photoelectron spectroscopy under additional optical excitation, the capacitive detection of the photoinduced displacement current in a parallel-plate capacitor geometry under modulated optical excitation, and the classical Kelvin probe technique. The methods are evaluated comparatively with …
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Optical Limiting and Degenerate Four-Wave Mixing in Novel Fullerenes
Two experimental methods, optical limiting and degenerate four-wave mixing, are employed to study the nonlinear optical properties of various novel fullerenes structures. Optical limiting refers to decreased transmittance of a material with increased incident light intensity. Detailed measurements …
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Ultrathin films on semiconductor substrates : growth, magneto-optical characteristics and spin injection
… especially their magneto-optical properties and spin injection.Magnetic ultrathin films were grown on different GaAs substrates using an e-beamevaporation technique. The MBE system which is used to fabricate and analyseultrathin films is home designed and assembled. The …
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