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 45 for “"Laser cavity"”.
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Solving an eigenvalue problem in laser simulation
… thesis a new and powerful approach for modeling laser cavity eigenmodes is presented. This approach is based on an eigenvalue problem for singularly perturbed partial differential operators with complex coefficients; such operators have not been investigated in detail until now. The eigenvalue …
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Intracavity coherent interaction of mode-locked pulse train with resonant medium
… of a mode-locked pulse train with intracavity samples, namely rubidium-87 (Rb-87) vapor and Fabry-Perot etalon, placed inside a laser cavity are studied in the light of developing ultra-sensitive laser sensors to measure a small magnetic field and a minute change of index of refraction …
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Noise and stability of actively modelocked fiber lasers
The timing jitter of a modelocked laser is fundamentally limited by the amplified spontaneous emission in the laser cavity. While one cannot, even in principle, remove this source of noise, one does have control over the pulse timing by using filtering and modulation. In this thesis, we report on …
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Applications of programmable MEMS micromirrors in laser systems
… scanning micromirrors, and their use as intracavity active Q-switch elements in solid-state laser systems, are investigated. The AVC scanning micromirrors are created through a multi-user fabrication process, with theoretical and experimental investigations undertaken on the influence of the …
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Coherent laser arrays from bottom-surface vertical-cavity surface-emitting lasers
Vertical-cavity surface-emitting lasers (VCSELs) are among the best choices for high beam quality semiconductor lasers. By designing a VCSEL array for uniform current injection and having the output coupler on the substrate side of the laser cavity, the laser will more easily operate in the …
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The impact of brillouin pump pre-amplification on multiwavelength brillouin-erbium fiber laser in linear cavity
Multiwavelength Brillouin Erbium Fiber Lasers (BEFLs) gain interest in recent decades due to their inherent characteristics such as narrow linewidth, high optical power and single frequency. Generation of multiple wavelengths is realizable through combination of Brillouin and Erbium-Doped Fiber …
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A new method of modelling tuneable lasers with functional composition
A new nonlinear model is proposed for tuneable lasers. Using the generalized nonlinear Schrodinger equation as a starting point, expressions for the transformations undergone by the pulse are derived for each of the five components (gain, loss, dispersion, modulation, and nonlinearity) within the …
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Frequency stability of a helium neon laser system with external cavity control
Many applications of gas lasers depend upon the extremely high spectral purity of their output signals. To fully exploit this remarkable spectral purity requires a high degree of frequency stabilization and laser mode control. In the past few years much effort has been expended in attempts to …
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Optimization of sub-10 femtosecond titanium sapphire lasers
Kerr-lens mode locked Ti:sapphire lasers are the backbone of most ultrafast and attosecond pulse generation systems. As such when building such systems the experimentalist desires an easy to use and robust system to produce femtosecond pulses for use in experiments. Towards this end I will discuss …
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A preconditioned Newton-Krylov method for computing steady-state pulse solutions of mode-locked lasers
… boundary value problem for a mode-locked laser cavity using a specially preconditioned matrix-implicit Newton-Krylov solver. Solutions are obtained at least an order of magnitude faster than with dynamic simulation, the standard method. Our method is demonstrated experimentally on a …
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Block copolymer photonic crystals : towards self-assembled active optical elements
… of block copolymer photonic crystals. First, a laser cavity using block copolymer based one-dimensional (1D) photonic crystals has been demonstrated. Optically pumped surface-emitting lasing has been obtained using a dye-doped polymers as the organic gain medium and the self-assembled block …
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Explanation and prediction of curious experimental phenomena in lasers and nonlinear optics
… investigations of Raman shifting and the Co:MgF₂ laser, results were obtained which would not have been expected from the typical theoretical picture. In the case of Raman shifting, the forward Stokes conversion was found to depend upon the pump bandwidth. Numerical modeling suggests that coupling …
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The effect of gain saturation on actively mode-locked laser pulses
… within pulse duration for actively node-locked lasers and to discuss its effects on the generated pulses. The population inversion, obtained analytically using a perturbation scheme, has been found to vary considerably within pulse envelope. An assumingly Gaussian pulse has been followed along …
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Controlling molecules with lasers and lasers with molecules
… of spin in molecules using shaped ultrafast lasers and the dynamics of those lasers when their cavities are modified to include programmable molecular masks. The ability to control quantum phenomena has had several large successes over the last decade. This field, known as Quantum Control, …
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Rare-earth doped aluminum oxide lasers for silicon photonics
… development, distributed Bragg reflector lasers were designed and fabricated in a CMOS foundry. The laser cavity was created by introducing gratings on either side of a Si3N4 waveguide. Er3+:Al2O3 was deposited in SiO2 trenches on top of the Si3N4 layer, eliminating the need for any …
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A Mathematical Model of the Dynamics of an Optically Pumped Codoped Solid State Laser System
… of an optically pumped codoped solid state laser system. The model comprises five first order, nonlinear, coupled, ordinary differential equations which describe the temporal evolution of the dopant electron populations in the laser crystal as well as the photon density in the laser cavity. …
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External cavity laser biosensor for label-free detection
… this work, we demonstrate a dual-mode external cavity laser (ECL) biosensor to address the desired needs. The utilization of photonic crystal resonant reflector biosensor as mode-selection filter enables high sensitivity, while the stimulated emission process in the laser cavity provides high …
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Surface-emitting lasers for communications: novel metal-cavity microlasers and high-contrast-grating tunable VCSELs
… experiments of surface-emitting semiconductor lasers is presented. The design of novel micro and nanolasers using metal cavities for optical confinement is discussed. Theoretical modeling of quantum-well and quantum-dot emission properties, as well as experimental characterization of their …
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Synthesis, design and characterization of a distributed feedback grating based non-linear optical chemosensor
… our efforts is the Distributed Feedback (DFB) laser cavity. The waveguide materials synthesized are Si and Ti inorganic matrices that were optimized for optical waveguiding by determining the appropriate film thickness, refractive index and film smoothness. Amplified stimulated emission was …
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Wavelength locking and determination in tunable lasers by gain voltage measurement
In this thesis, tunable lasers under optical feedback are investigated. The influence of feedback on the spectral behaviour of the voltage at the gain section, the output power, the threshold current, the linewidth and the side mode suppression ratio are investigated. The findings complement the …
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