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 52 for “"Phase matching"”.
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Phase-Matching Optimization of Laser High-Order Harmonics Generated in a Gas Cell
… within the laser focus and to investigate phase matching. The phase matching under optimized harmonic generation conditions was found to be unexpectedly good with phase zones many millimeters long. Restricting the laser beam with an 8 mm aperture in front of the focusing lens increases the …
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Controlling Laser High-Order Harmonic Generation Using Weak Counter-Propagating Light
… light creates a standing intensity and phase modulation on the field, which disrupts microscopic phase matching and shuts down local high harmonic production. Suppression of the 23rd harmonic (by two orders of magnitude) is observed when a counter-propagating interfering pulse of light …
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Applications of optical parametric downconversion : I. Self-phase locking, [and] II. Generation of entangled photon pairs in periodically-poled lithium niobate
… nonlinear interactions through the use of quasi-phase matching, have increased the flexibility and performance of many nonlinear optical devices. One of the devices presented in this thesis is a 2:1 frequency divider based on self-phase locking in a type-II phase matched optical parametric …
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Generation and characterization of spectrally factorable biphotons
… KTiOPO₄ (PPKTP) crystal under extended Gaussian phase-matching conditions. The high purity achieved is made possible by the Gaussian phase-matching function of our custom PPKTP crystal. Without applying spectral filtering and using a standard PPKTP crystal, the highest previously reported purity …
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Second-Order Nonlinear Optical Responses in Tapered Optical Fibers with Self-Assembled Organic Multilayers
… SHG power compared to the traditional tapers. Phase matching for a SHG process in second-order nonlinear tapered fibers is also realized by the compensation of waveguide modal dispersion with material chromatic dispersion, which occurs only for submicron tapers where the modal dispersion is …
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Harmonic and Supercontinuum Generation in Zinc-Blende Materials
… structured semiconductors, relaxed phase matching conditions greatly extend the limits of frequency conversion imposed by acceptance bandwidth. Due to large nonlinearities and broad transparency window in the MIR, zinc-blende materials in their polycrystalline form are uniquely …
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Nonlinear aluminum nitride photonic crystal measurement using tapered fiber
… of nonlinear coupling interaction strength, the phase matching of the mode extraction from the waveguide to the ring resonator, and the fabrication of tapered optical fiber and tapered aluminum nitride waveguide.
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Stimulated Brillouin scattering in an on-chip microdisk resonator
… SBS lasers, microwave oscillators, optical phase conjugation and slow light. Nonlinear optical phenomena can be enhanced in resonant systems due to the significantly increased interaction times between photons. In this regard, the SBS nonlinearity has already been demonstrated in resonators …
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Numerical Analysis of Optically-induced Long-period Fiber Gratings for Sensing Applications
… discrete co-propagating cladding modes when the phase matching condition is satisfied. The rapid attenuation of cladding modes results in loss bands in the transmission spectrum. As the attenuation bands are sensitive to the LPG period and the fiber surrounding environment such as temperature, …
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Generation of fiber-coupled, nondegenerate, polarization-entangled photons for quantum communication
… processing. In this thesis, we use type-0 phase-matched downconversion of pump photons from a 532 nm continuous-wave laser to generate 798 nm signal and 1.6 tim idler photon pairs in periodically-poled, congruent lithium niobate (PPLN). Difference frequency generation of 798 nm is used for …
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Long-Period Gratings as Immuno-Diagnostic biosensors
… to the coupled wavelengths. Based on the phase-matching condition between the coupling and coupled modes, the loss bands shift with changes in the refractive index of the surrounding medium. The grating surface is chemically treated to covalently bond antibody to the cladding of the …
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Fiber-taper collected photoluminescence characterization of diamond microdisks
… that coupling to these disks may be limited by phase matching requirements. By thinning these disks it should be possible to improve coupling while lowering mode volumes, as desired to optimize Purcell factors.
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Second harmonic generation in novel optical waveguides
… sophisticated fabrication technology, poling and phase matching techniques, it has now become feasible in glass fibres and waveguides which are widely used in nonlinear optics. For instance, silica glass based Photonic Crystal Fibres (PCF) exhibit long coherence lengths and controllable optical …
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Investigation of nonlinear processes and device designs applicable to the creation of a compact, broadly tunable laser based on a tantalum pentoxide planar lightwave circuit platform
Nonlinear photonic devices utilize phase-matched parametric wavelength conversion in a nonlinear medium to create a widely tunable pulsed laser source. Currently most of nonlinear lasers are based on bulk optics or photonic fibres. Lasers based on bulk optics utilizing nonlinear crystals in …
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High frequency AC power converter for low voltage circuits
… is suitable for VHF frequency (50-100MHz) polyphase AC/DC power conversion in low voltage integrated circuits. A complete AC power delivery architecture was evaluated demonstrating the benefits of delivering power across the interconnect at high voltage and lower current with on- or over-die …
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Brillouin scattering induced transparency and generation of slow and fast light
… the two optical modes that are coupled through a phase matched acoustic mode. The coherent coupling of two energy levels is emulated by the acousto-optic interaction of Brillouin scattering. The probe phase response is analyzed to estimate BSIT's effect on the velocity of light pulse. As BSIT …
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Nonlinear Microscopy for Materials Analysis and Clinical Pathology
… was conducted. State-of-the-art poling for quasi phase matching was achieved via an iterative process. Devices were poled in a custom-built high voltage probing setup and imaged with a second harmonic generation (SHG) microscope to provide feedback on the poling parameters. A select number of …
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Cephalometric Evaluation of One-Phase and Two-Phase Treatment Alternatives in Matched Class Ii Subjects
<p>“Early” or two-phase orthodontic treatment of Class II malocclusions is a highly debated topic in the orthodontic literature. We report here on a retrospective cephalometric study of patients with Class II, division 1 malocclusions. One group consisted of 32 consecutively treated patients who …
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Root Morphology and Sexual Dimorphism : Size Standards for Crown and Root Dimensions in Adolescents
<p>“Early” or two-phase orthodontic treatment of Class II malocclusions is a highly debated topic in the orthodontic literature. We report here on a retrospective cephalometric study of patients with Class II, division 1 malocclusions. One group consisted of 32 consecutively treated patients who …
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High performance photon-pair source based on a fiber-coupled periodically poled KTiOPO₄ waveguide
… of photon pairs at 1316 nm in a type-II phasematched Rb-indiffused waveguide in periodically poled KTiOPO4 (PPKTP). We perform the flux and spectrum characterization of our integrated waveguide source, and obtain a pair production rate of 2 x 107/s/mW in a 1.08-nm bandwidth. The …
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