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 106 for “"Wave mixing"”.
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Chirality Determination Using Three-Wave Mixing Microwave Spectroscopy
… has stemmed from both advancements in microwave technology and a willingness from the community to push the boundaries of the field. In this dissertation, the boundaries are tested in both how well the technique can determine the structure of molecules exhibiting large amplitude motion and …
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Four-Wave Mixing in Distributed-Feedback Semiconductor Lasers
… we present measurements of dual-pump four-wave mixing in distributed-feedback lasers with two lasing modes for both the parallel and orthogonally polarizations. For the parallel case, we develop a comprehensive model for dual-pump four-wave mixing. The experiments show that the conversion …
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Four-wave mixing with hermite-gauss modes in rubidium vapor
… of coherent light generated in a forward four-wave mixing (FWM) process. We are interested in investigating how the transverse structure of the incident beams, more specifically of the Hermite-Gauss (HG) modes, is transferred to the generated signal in this nonlinear process. For the …
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Optical Limiting and Degenerate Four-Wave Mixing in Novel Fullerenes
… 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 of the …
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Wavelength conversion by four wave mixing in passive InGaAsP/InP waveguides
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
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Breaking the Cycle: the Rise and Fall of Conversion Cycle Limited Three-Wave Mixing
… the spatiotemporal intensity profiles of the mixing laser fields. We introduce a new method for achieving efficient OPA by using simultaneously phase-matched idler second harmonic generation (SHG) to act as an effective loss-channel for idler photons. The dynamics are characterized by damped …
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Probing the Dissociation of the Rubidium Dimer by Wavepackets and Parametric Four-Wave Mixing
Embargo set by: Seth Robbins for item 82331 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs
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Characterization of II-VI semiconductor nanostructures by low wavenumber raman- and four-wave-mixing spectroscopy
Es ist bekannt, dass räumlich eingeschränkte Ladungsträger in niederdimensionalen Halbleitern zur Verstärkung optischer und elektronischer Eigenschaften solcher Nanostrukturen beitragen. Die Physik des "Quantum Confinements" ist trotz umfangreicher Nachforschungen noch immer nicht völlig …
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Four-Wave Mixing Techniques Applied to the Investigation of Non-Adiabatic Dynamics in Polyatomic Molecules
… within the framework of time-resolved, four-wave mixing spectroscopy were developed that allowed for the dynamic as well as the energetic aspects of vibronic coupling in non-radiative transitions of polyatomic molecules to be addressed. This was achieved by utilizing the influence of optical …
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Investigation of Degenerate Four -Wave Mixing and Polarization Spectroscopy for Quantitative Measurements in Combustion Environments
The application of DFWM and PS for quantitative concentration measurements was investigated experimentally by measuring lineshapes and signal intensities in well-characterized hydrogen/air flames. Resonances in the A2Sigma +-X2pi (0,0) band of hydroxyl (OH) were probed with both perturbative and …
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Ultrafast Transient Absorption and Multi-Wave Mixing Spectroscopies in the Extreme Ultraviolet and Soft X-RAY Regimes
… temporal resolution in a novel three-color wave mixing spectroscopic scheme. The proposed three-color scheme provides additional advantages in accessing excited dark states through background-free emission by exploiting non-commensurate probe IR fields. Finally, we provide technical …
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Detection and assessment of high temperature hydrogen attack in steel pressure vessels using non-collinear wave mixing
… A strategy of detection involving non-collinear wave mixing of ultrasonic waves and pulse-inversion is illustrated using a test sample extracted from a retired pressure vessel. Results show that nonlinear ultrasonics are capable of detecting and evaluating HTHA damage over the thickness of the …
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Non-destructive quantitative assessment of oxidation in aged and rejuvenated asphalt concrete pavements using a non-collinear wave mixing approach
… addresses this need by employing non-collinear wave mixing, a nonlinear acoustic technique, to evaluate the level of oxidation of the pavement. To implement the nonlinear technique, the linear acoustic parameters, i.e., dilatational and shear velocities and attenuations, of asphalt concrete …
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Quantum beat observations in rubidium vapor
… 5D_{5/2} energy states were observed by a four-wave mixing process. The difference frequency between the 5D–5P_{3/2} and the 5P_{3/2}–5S transitions was also observed for interpulse delays up to 180 ps. The temporal evolution of the beat amplitude indicates the existence of a superfluorescent …
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Nonlinear optical effects in nematic liquid crystals
… liquid crystals including degenerate four-wave mixing are presented. The optically induced Freedericksz transition which is essential for these effects is also described. Experimental investigations are performed using a homeotropically aligned MBBA thin film. Good agreement is obtained …
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Damage evaluation in dimension limestone using nonlinear ultrasonics
… in the form of a non-collinear ultrasonic wave mixing approach. In addition, the test samples’ degradation of flexure strength due to damage accumulation caused by the exposure to increasing levels of temperature was also obtained using four-point bending tests. Results using the currently …
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CORRELATED PHOTON PAIRS AND MULTIPHOTON STATES FROM A COLD ATOMIC ENSEMBLE
… correlated photon-pair source at near-resonant wavelengths of 780 nm and 795 nm in an optically dense cold <sup>87</sup>Rb ensemble. The source is based on a spontaneous four-wave mixing process implemented in a double-Λ energy-level configuration. By systematically varying the pump …
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Holographic lasers
… cavity by phase conjugation. A fibre based four-wave mixing scheme is investigated but no experimental evidence of any phase conjugation is observed.
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Impacts of higher-order dispersion coefficients and dispersion fluctuations on one-pump fiber optical parametric amplifier
Four-wave mixing (FWM) is a nonlinear effect in optical fiber which is useful for fiber optical parametric amplifiers (FOPA). The performance of FOPA i.e. parametric gain, amplification bandwidth, and saturation power are reliant on the efficiency of the FWM process. The random dispersion …
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