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Qing Hu. Kohen, Stephen Michael, 1980- Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science 2005-06-02T19:48:26Z 2005-06-02T19:48:26Z 2004 2004 http://hdl.handle.net/1721.1/18058 57400862 Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004. Page 108 blank. Includes bibliographical references (p. 103-107). Finite-element numerical modeling and analysis of electromagnetic waveguides and resonators used in terahertz (THz) quantum cascade lasers (QCLs) is presented. Simulations and analysis of two types were performed: two-dimensional waveguides, and two- and three-dimensional resonators. Both metal-metal and semi-insulating (SI) surface-plasmon geometries were investigated. Waveguide simulations extend previous one-dimensional analyses to two dimensions; resonator simulations in two and three dimensions are presented for the first time. The waveguide simulations quantitatively show when two-dimensional effects become non-negligible in their effect titatively show when two-dimensional effects become non-negligible in their effect on the figure-of-merit relative to previous one-dimensional analyses. The resonator simulations quantitatively show the hybrid optical/microwave nature of THz facet reflectivities, demonstrating that both the effective index method and the impedance mismatch method are poor methods in calculating mirror reflectivities for metal-metal waveguides in the THz region. The effective index method is shown to still be valid for SI surface-plasmon waveguides. In addition, simulated radiation patterns are presented for both waveguiding structures. by Stephen Michael Kohen. S.M. 108 p. 5359313 bytes 5372069 bytes application/pdf application/pdf eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Electrical Engineering and Computer Science. Electromagnetic modeling of terahertz quantum cascade laser waveguides and resonators Electromagnetic modeling of THz QCL waveguides and resonators Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="cd58b7d7-e940-493c-bbcb-19a6a4fff8d1"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Electromagnetic modeling of terahertz quantum cascade laser waveguides and resonators</Title> <Subtitle>Electromagnetic modeling of THz QCL waveguides and resonators</Subtitle> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2004</PublicationDate> <Authors> <Author> <DisplayName>Kohen, Stephen Michael, 1980-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Electrical Engineering and Computer Science.</Keyword> <Abstract>Finite-element numerical modeling and analysis of electromagnetic waveguides and resonators used in terahertz (THz) quantum cascade lasers (QCLs) is presented. Simulations and analysis of two types were performed: two-dimensional waveguides, and two- and three-dimensional resonators. Both metal-metal and semi-insulating (SI) surface-plasmon geometries were investigated. Waveguide simulations extend previous one-dimensional analyses to two dimensions; resonator simulations in two and three dimensions are presented for the first time. The waveguide simulations quantitatively show when two-dimensional effects become non-negligible in their effect titatively show when two-dimensional effects become non-negligible in their effect on the figure-of-merit relative to previous one-dimensional analyses. The resonator simulations quantitatively show the hybrid optical/microwave nature of THz facet reflectivities, demonstrating that both the effective index method and the impedance mismatch method are poor methods in calculating mirror reflectivities for metal-metal waveguides in the THz region. The effective index method is shown to still be valid for SI surface-plasmon waveguides. In addition, simulated radiation patterns are presented for both waveguiding structures.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>