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 169 for “"Lasing"”.
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Controlled Lasing in Gallium Nitride Nanowires
… semiconductors. However, due to the limited lasing control techniques, most of the nanowire lasers operate in naturally-occurring multi-mode and randomly polarized states. Lasing control in nanowire lasers is strongly desired for many practical applications. For instance, specifically …
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Lasing From Single Film-Coupled Nanoparticles
… for low-threshold, room-temperature nanolasing that can be predicted analytically. In this dissertation, I present results from multiphysical numerical models used to validate the predictions of a recent analytical theory, using optical pump intensity, population inversion, and pump …
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Band edge lasing in chiral nematic liquid crystals
… liquid crystal at the band edges, resulting in lasing. Applications of liquid crystal lasers could include miniature medical diagnostic tools, large-area holographic laser displays, and environmental sensing. The wavelength of emission from dye-doped chiral nematic liquid crystals is highly …
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Low threshold random lasing from phase separated optical fibers.
… reduced length of scattering fiber (4 m) for lasing. The enhanced Rayleigh scattering was verified through measurements and a new figure of merit called effective power reflectivity was also developed to quantify random feedback. With a Yb-doped fiber as the gain medium, the fiber laser …
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Advanced silicon photonic microcavities for routing, detection and lasing applications
… for optical signal routing, detection, and lasing applications. We first introduce partial-drop filters and present results using them to achieve a highly uniform wavelength-division-multiplexing (WDM) compatible optical multicast system. We then implement a waveguide-coupled resonant …
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Novel II-IV semiconductor nanocrystal gain media : from amplified spontaneous emission to lasing
… (CdSe) nanocrystallites (NCs) as a novel lasing media. We begin with the synthesis of polymer/NC composites, in which the NCs are stabilized within a long-chain methacrylate polymer. This chapter serves to highlight the processing flexibility afforded by the NCs as well as some of the …
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Quenching and lasing effects in erbium-doped fibers made with alkaline earth fluoride nanoparticles
… in optical fiber is highly valued for its use in lasing and amplification. However, the scalability of erbium-doped fibers (EDFs) has been limited by the natural likelihood of the rare earth ion to cluster in silicate glasses. When the ions cluster, they continuously trade energy with each other, …
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Stimulated Raman scattering, lasing, and molecular energy transfer mechanisms in KXe probed by laser spectroscopy
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2025-08-01
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Study of the physics of the power-scaling of end-pumped solid-state laser sources based on Nd:YVO<sub>4</sub>
… lensing. Comparing the thermal lensing under lasing and non-lasing conditions demonstrated that the heating in the laser crystal under non-lasing conditions is significantly greater than under lasing conditions. The thermal lenses are almost 5 times stronger under non-lasing conditions than …
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Low threshold organic and quantum dot nanobeam lasers
… materials have been used to demonstrate low lasing thresholds, and we hope to improve upon them with a novel design, paving the way towards electrically pumped and continuous wave operation lasing. In this thesis we couple the use of organic materials and quantum dots with one dimensional …
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Planar waveguide devices fabricated by pulsed laser deposition
… for the first time by PLD and has achieved lasing action at a threshold of 14.8 mW of absorbed power. Comparison of the lasing threshold to that of similar uncapped devices demonstrate that the capped layer has a highly beneficial effect on the lasing threshold when the particulate density …
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Top-down Cross-Section Controlled III-Nitride Nanowire Lasers
… For practical applications, control over the lasing properties is needed. For example, a single mode lasing is beneficial for reducing the pulse broadening and the signal errors during the optical communications. An annular-shaped beam could be potentially used for the atom trapping or the …
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Design and Characterization of Quantum-Cascade Lasers
… bound-to-continuum QCL is observed with the lasing wavelength of 104 mum. The light-current-voltage characteristics as well as the lasing spectrum are measured at different temperature. The characteristic temperature is extracted to be 144 K, while the quantum efficiency is found to be around …
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Theoretical and experimental studies of optically pumped molecular gas lasers
… Nd:YAG laser that pumped HBr were accomplished. Lasing at 4 microns was demonstrated from such a system. We identified acetylene and hydrogen cyanide as potential laser gases that can be pumped with lasers emitting in the attractive telecommunication C band region at about 1.5 microns. …
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Integrated Multiwavelength Semiconductor Lasers
… technical challenge is to increase the number of lasing modes with as much control over the wavelength and linewidth as in today's single-wavelength semiconductor lasers. By utilizing multiple sections of periodic structures, dual-wavelength InGaAs-GaAs ridge waveguide semiconductor lasers have …
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An overview of laser operation and modelocking of a vertical external cavity surface emitting laser (VECSEL)
… lasers. They exhibit a combination of desirable lasing features that are usually not simultaneously attainable. These features are high power, diffraction limited beam quality, intra-cavity frequency doubling, tunability, and ultrashort pulses generated from passive mode-locking. In this work, we …
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Correlative elemental and electrical micro-analysis of laser fired contacts in silicon solar cells
… using two lasers simultaneously (double-shot lasing) versus a single laser for LFC processing, and (2) using the new findings to optimize industrial LFC efforts. Electrical properties such as lifetime degradation and contact resistance are evaluated using photoluminescence imaging and …
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Resonant Raman scattering studies of III-V semiconductor microstructures
… structural results, and a phonon-assisted lasing project underscores electron-phonon interaction. The disorder-induced frequency difference between the dipoleforbidden and dipole-allowed longitudinal optic (LO) modes in AlxGa 1_xA s alloys has been investigated as a function of laser photon …
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Hybrid laser with CMOS photonics
… gain mediums into CMOS processes, allowing for lasing at virtually arbitrary wavelengths, the possibility of multiwavelength operation with a shared gain medium, elimination of closed-loop control of wavelength tuning, ability to control laser output and wavelength on-chip, and the potential for …
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