{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25350"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25350","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"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","abstract":"\"The work described ir. this thesis involves the study of optical ar.d thermal propterties of semicor.ductors and consists of three seperate topics. 1. Resonant two-photon absorption by exciton polaritons in CuCl ~. A study of the lineshape and intersity of the biexciton decay luminescerce reveals a two-photon reabsorption process in which the longitudinal exciton and the transverse polaritor act as resonant intermediate states. Dispersion informatior or these states at large momertum is produced and a simplified theory of the resonant resonant reabsorption process is described. 2.Heat pulse propagation across metal/sapphire 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 exhibts a local but nonsingular maximum. These features are termed \"\"precursors\"\" because they will transform into normal singularities if the elastic constants are modified slightly. These two types of features are readily predicted by classical elasticity theory. The third type of feature is a surface effect in which a consentration of transverse phonons near the critical cone for mode conversion from bulk transverse waves to longitudinal waves along the surface. It is found to be dependent on surface orientation and is very sensitive to surface quality. A theory by A. Every is described in which this feature is due to a longitudinal pseudo-surface wave on free or weakly bonded surfaces. 3. Phonon Focusing in Piezoelectric Crystals. The calculation of phonon focusing patterns through classical elasticity theory is extended to include the piezoelectric effect in the quasistatic limit through the use of \"\"stiffened\"\" elastic constants. Good agreement between experimental and theoretical predictions is obtained. While the effect is small fora-quartz it is dramatic for lithium niobate.\"","abstract_html":""The work described ir. this thesis involves the study of optical ar.d thermal propterties of semicor.ductors and consists of three seperate topics. 1. Resonant two-photon absorption by exciton polaritons in CuCl ~. A study of the lineshape and intersity of the biexciton decay luminescerce reveals a two-photon reabsorption process in which the longitudinal exciton and the transverse polaritor act as resonant intermediate states. Dispersion informatior or these states at large momertum is produced and a simplified theory of the resonant resonant reabsorption process is described. 2.Heat pulse propagation across metal/sapphire 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 exhibts a local but nonsingular maximum. These features are termed ""precursors"" because they will transform into normal singularities if the elastic constants are modified slightly. These two types of features are readily predicted by classical elasticity theory. The third type of feature is a surface effect in which a consentration of transverse phonons near the critical cone for mode conversion from bulk transverse waves to longitudinal waves along the surface. It is found to be dependent on surface orientation and is very sensitive to surface quality. A theory by A. Every is described in which this feature is due to a longitudinal pseudo-surface wave on free or weakly bonded surfaces. 3. Phonon Focusing in Piezoelectric Crystals. The calculation of phonon focusing patterns through classical elasticity theory is extended to include the piezoelectric effect in the quasistatic limit through the use of ""stiffened"" elastic constants. Good agreement between experimental and theoretical predictions is obtained. While the effect is small fora-quartz it is dramatic for lithium niobate."","abstract_has_math":false,"creators":["Koos, Gregory Lee"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Wolfe, J.P."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-06-08T15:10:23Z","date_published":"2011-06-08T15:10:23Z","updated_at":"2026-07-22T22:25:24Z","subjects":["resonant two-photon reabsorption","exciton-polaritons","cuprous chloride films","heat pulse propagation","metal/sapphire interfaces","phonon focusing","piezoelectric crystals"],"languages":["en"],"rights":["1984 Gregory Lee Koos"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["824805"],"render_values":[{"text":"824805","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25350","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Wolfe, J.P."]},{"key":"dc:creator","label":"Author","values":["Koos, Gregory Lee"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-06-08T15:10:23Z","10000-01-01","1984"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["resonant two-photon reabsorption","exciton-polaritons","cuprous chloride films","heat pulse propagation","metal/sapphire interfaces","phonon focusing","piezoelectric crystals"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1984 Gregory Lee Koos"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["824805","http://hdl.handle.net/2142/25350"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["\"The work described ir. this thesis involves the study of optical ar.d thermal propterties of semicor.ductors and consists of three seperate topics. 1. Resonant two-photon absorption by exciton polaritons in CuCl ~. A study of the lineshape and intersity of the biexciton decay luminescerce reveals a two-photon reabsorption process in which the longitudinal exciton and the transverse polaritor act as resonant intermediate states. Dispersion informatior or these states at large momertum is produced and a simplified theory of the resonant resonant reabsorption process is described. 2.Heat pulse propagation across metal/sapphire 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 exhibts a local but nonsingular maximum. These features are termed \"\"precursors\"\" because they will transform into normal singularities if the elastic constants are modified slightly. These two types of features are readily predicted by classical elasticity theory. The third type of feature is a surface effect in which a consentration of transverse phonons near the critical cone for mode conversion from bulk transverse waves to longitudinal waves along the surface. It is found to be dependent on surface orientation and is very sensitive to surface quality. A theory by A. Every is described in which this feature is due to a longitudinal pseudo-surface wave on free or weakly bonded surfaces. 3. Phonon Focusing in Piezoelectric Crystals. The calculation of phonon focusing patterns through classical elasticity theory is extended to include the piezoelectric effect in the quasistatic limit through the use of \"\"stiffened\"\" elastic constants. Good agreement between experimental and theoretical predictions is obtained. While the effect is small fora-quartz it is dramatic for lithium niobate.\"","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-08T15:10:23Z No. of bitstreams: 1 1984_koos.pdf: 4790602 bytes, checksum: 31a5e8bf67a9c5efe2178a03eb85f54c (MD5)","Made available in DSpace on 2011-06-08T15:10:23Z (GMT). No. of bitstreams: 1 1984_koos.pdf: 4790602 bytes, checksum: 31a5e8bf67a9c5efe2178a03eb85f54c (MD5) Previous issue date: 1984","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-08T15:10:23Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:09:30-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["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"]}]}],"canonical_facts":{"dc:contributor":["Wolfe, J.P."],"dc:creator":["Koos, Gregory Lee"],"dc:date":["2011-06-08T15:10:23Z","10000-01-01","1984"],"dc:description":["\"The work described ir. this thesis involves the study of optical ar.d thermal propterties of semicor.ductors and consists of three seperate topics. 1. Resonant two-photon absorption by exciton polaritons in CuCl ~. A study of the lineshape and intersity of the biexciton decay luminescerce reveals a two-photon reabsorption process in which the longitudinal exciton and the transverse polaritor act as resonant intermediate states. Dispersion informatior or these states at large momertum is produced and a simplified theory of the resonant resonant reabsorption process is described. 2.Heat pulse propagation across metal/sapphire 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 exhibts a local but nonsingular maximum. These features are termed \"\"precursors\"\" because they will transform into normal singularities if the elastic constants are modified slightly. These two types of features are readily predicted by classical elasticity theory. The third type of feature is a surface effect in which a consentration of transverse phonons near the critical cone for mode conversion from bulk transverse waves to longitudinal waves along the surface. It is found to be dependent on surface orientation and is very sensitive to surface quality. A theory by A. Every is described in which this feature is due to a longitudinal pseudo-surface wave on free or weakly bonded surfaces. 3. Phonon Focusing in Piezoelectric Crystals. The calculation of phonon focusing patterns through classical elasticity theory is extended to include the piezoelectric effect in the quasistatic limit through the use of \"\"stiffened\"\" elastic constants. Good agreement between experimental and theoretical predictions is obtained. While the effect is small fora-quartz it is dramatic for lithium niobate.\"","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-08T15:10:23Z No. of bitstreams: 1 1984_koos.pdf: 4790602 bytes, checksum: 31a5e8bf67a9c5efe2178a03eb85f54c (MD5)","Made available in DSpace on 2011-06-08T15:10:23Z (GMT). No. of bitstreams: 1 1984_koos.pdf: 4790602 bytes, checksum: 31a5e8bf67a9c5efe2178a03eb85f54c (MD5) Previous issue date: 1984","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-08T15:10:23Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:09:30-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"],"dc:identifier":["824805","http://hdl.handle.net/2142/25350"],"dc:language":["en"],"dc:rights":["1984 Gregory Lee Koos"],"dc:subject":["resonant two-photon reabsorption","exciton-polaritons","cuprous chloride films","heat pulse propagation","metal/sapphire interfaces","phonon focusing","piezoelectric crystals"],"dc:title":["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"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:24Z"}