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 17 of 17 for “"Spectral phase"”.
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SPINS : spectral phase interrogation using nonlinear spectra
… on the measured fundmental spectrum and a trial phase. The phase is adjusted iteratively until the best match between the trial and measured SHG and THG spectra is obtained. The technique is experimentally simple, not subject to delicate temporal alignments, and potentially insensitive to …
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Few-cycle and cavity-enhanced optical parametric amplification
… large gain bandwidths, to wide array of spectral ranges. The work reported in this thesis relates to two areas for the continued development of optical parametric amplification based sources. First, we present a white light seeded, carrier-envelope stable, degenerately pumped OPA …
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Characterization and control of the nonlinear optical properties of dendritic silver nanoparticle clusters
… can be controlled by the polarization and spectral phase of the laser used for excitation.Studies into the properties of emission show that the emission is a two-photon induced luminescence, enhanced by localization of the electric field by the silver nanoparticles. The spatial distribution …
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Development and spatio-spectral mapping of a capillary high harmonic source
… of the capillary launch). A study of the spectral output of the system as a function of gas pressure, laser power, and laser spectral phase. An analysis technique for recovering spatially-resolved spectral information about a beam by studying the Fresnel diffraction pattern produced at an …
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Femtosecond pulse shaping for enhanced optical imaging and control of cells
… grows rapidly. Unfortunately, the significant spectral overlap in probe responsiveness presents limitations on their potential applications. Much of the effort in circumventing this issue has been focused on developing modified probes with shifted spectral sensitivities; however, this is a long …
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The development of high power fibre chirped pulse amplification systems
… novel fiber CPA system operating with strong selfphase-modulation (SPM) is described, which applied adaptive shaping of the spectral phase of the input pulses. The pre-compensation of both SPM induced phase distortion at high energies, and residual dispersion from mismatched stretcher/compressor …
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Studying Ultrafast Vibrational dynamics of Intramolecular Hydrogen Bonds using Broadband Infrared Pump-Probe Spectroscopy.
… broadband mid-infrared (BBIR) source with the spectral range of 2-8 microns. The broadband pulse enables us to perform novel experiments in multiple domains (both in infrared and electronic) to understand energy transfer dynamics and vibrational couplings of very broad peaks. The tunable BBIR …
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Interaction of a finite train of short optical pulses with a ladder system
… A train of pulses produced by shaping the spectral phase of a single pulse from an ultra fast laser allows us to control the step-wise excitation in rubidium (Rb) atoms. As a diagnostic method, we use magneto-optical trap recoil ion momentum spectroscopy (MOTRIMS) to prepare cold target …
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High-dimensional Quantum Key Distribution with Frequency Encoding
… (SPDC) process through custom engineering of phase-matching conditions. The heralded single-photon source is useful in measurement-based quantum applications, where indistinguishable single photons are required to ensure high-visibility photon-photon interference. The second part of this …
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Entrainment Characteristics of Turbulent Round Gas Jets Submerged in Water
The entrainment process in two-phase buoyant jets differs significantly from their singlephase counterparts, and is not well understood. Entrainment models developed for singlephase flow are often used in two-phase jetting simulations, albeit with limited success. In this work, Particle Image …
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Cross-Spectral Analysis For Spatial Point-Lattice Processes
… arid a lattice process using two-dimensional spectral techniques. Simulated spatial point-lattice patterns are used to demonstrate how the different cross-spectral statistics can reveal correlation between the two components. A method to adjust for jumps that normally occur in the …
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Development of Robust Correlation Algorithms for Image Velocimetry using Advanced Filtering
… These techniques incorporate the use of the Phase Transform (PHAT) Generalized Cross Correlation (GCC) filter applied to the image cross-correlation. The use of spatial windowing is subsequently examined and shown to be ideally suited for the use of phase correlation estimators, due to their …
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The role of near time coherent contrast on ultrafast laser driven radiation sources
… 40 examine the effect of third order dispersion (spectral phase) on high harmonic generation. The third order dispersion (TOD) changes the shape of the incident pulse creating either leading or trailing satellite pulses which can influence the harmonics generated. A scan of TOD is undertaken, and …
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Phase-and-Defect Diagrams for Polycrystalline Grain Boundary Segregation
… (NC) alloys. Traditionally, bulk equilibrium phases have been considered in a decoupled manner from defects, such as solute and segregated atoms, dislocations, and grain boundaries. In recent years, a push has been made to treat defects as “defect states” in a manner analogous to bulk phases …
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Sub-femtosecond precision timing distribution, synchronization and coherent synthesis of ultrafast lasers
… pulse trains, with respect to pulse timing and phase. First, analytical analysis of the balanced optical cross-correlator (BOC) for attosecond precision pulse timing measurement is presented for both short and long crystal devices. It is found that the sensitivity of the long crystal BOC is …
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Coherent Control of Molecular Dynamics with Shaped Femtosecond Pulses
… for a predefined target wave function via a phasecorrect superposition of wave functions. The goal of coherent control, the selective preparation of a target state, is an important prerequisite for mode-selective chemistry. The laser pulse tailored to drive the system from the initial to the …