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 9 of 9 for “"phonon focusing"”.
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I. Resonant Two-Photon Reabsorption by Exciton-Polaritons in Cuprous Chloride Films. Ii. Heat Pulse Propagation Across Metal/sapphire Interfaces. Iii. Phonon Focusing in Piezoelectric Crystals
The work described in this thesis involves the study of optical and thermal properties of semiconductors and consists of three separate topics.
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I. Resonant two-proton reabsorption by exition-polaritons in cuprous chloride films ; II. Heat pulse progration across metal/sapphire interfaces ; III. Phonon focusing in piezoelectric crystals
… interfaces. The angular dependerce of ballistic phonon propagatior ir sapphire is found to exhibit three distinct types of features. The first corresponds to mathematical singularities in the bulk phonon focusing. The second type of feature observed corresponds directions in which the phonon flux …
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Phonon imaging
This thesis describes the development of the phonon imaging method. This technique permits the direct measurement of the angular and temporal distribution of phonons emitted from a point source of heat in insulators at low temperatures. It is a derivative of the ballistic heat pulse method, but one …
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High frequency phonon propagation and detection in III-V semiconductors
… and detection of high frequency acoustic phonons in GaAs and InAs is studied. .Phonon imaging is used to study scattering of acoustic phonons in GaAs and angular dispersion of acoustic phonons in InAs. Photoluminescence spectroscopy is used to study the effects of nonequilibrium phonons on …
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The scattering of high-frequency acoustic phonons in silicon and GaAs
… and propagation of high-frequency acoustic phonons in silicon and GaAs are studied at low temperatures (~ 2K) using the phonon imaging technique. In this technique, a heat source is provided by a focused laser beam which is raster scanned across the surface of the sample which is immersed in …
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Study of phonon transmission through solid-solid interfaces and superlattices by phonon imaging
… the low-temperature propagation of heat pulses (phonons) through crystals and across solid-solid interfaces. The phonon imaging technique has been used to examine the angular and temporal dependence of the phonon-flux intensity in several systems, listed below. 1. Phonon focusing in cubic …
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The scattering of high-frequency acoustic phonons in silicon and gallium arsenide
… and propagation of high-frequency acoustic phonons in silicon and GaAs are studied at low temperatures ($\le$2K) using the phonon imaging technique. In this technique, a heat source is provided by a focused laser beam which is raster scanned across the surface of the sample which is immersed …
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Study of phonon-dislocation interaction in LiF and KCl crystals
… provides a useful tool for the study of phonon-dislocation interaction. In this thesis, thermal conductivity measurements on plastically deformed LiF and KCl crystals are discussed. LiF crystals were deformed in such a way that four slip systems were activated, in a hope to better …
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Dispersive phonon imaging in III-V semiconductors
… transport properties of high-frequency acoustic phonons are investigated in GaAs, InSb, InP and InAs using the phonon-imaging technique. In this method, a focused laser beam provides a movable heat source on one side of a cooled crystal (~ 2 K). A single small phonon detector on the opposite face …