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dc.contributor.authorKim, Joong Hyunen_US
dc.date.accessioned2009-01-22T15:49:56Z
dc.date.available2009-01-22T15:49:56Z
dc.date.issued2008-11-17en_US
dc.identifier.urihttp://hdl.handle.net/1853/26608
dc.description.abstractThe photoconductive method is one of the oldest methods for the generation of THz room temperature operated THz electromagnetic waves. The THz photoconductive source has operated at a lower power level in the order of hundreds of nW. In addition, the energy conversion of optical to THz efficiency has remained extremely low. One of the most efficient THz photoconductive sources is a trap-enhanced field (TEF) effect source. The field is measured to contain more than 90% of the total DC bias within the first 5 µm of an 80 µm gap between the electrodes reaching kV/cm with only a modest bias. The overall THz power, however, has remained low, due to its rapid saturation. To date, there has been a limited understanding of the TEF effect. In this thesis, a more detailed experimental investigation of TEF effect current transport and field distribution based on annealing is presented to explain some of the underlining physics of TEF effect. A spatially extended line excitation is introduced to effectively reduce the screening effect while still exploiting the TEF region to maintain high efficiency and reach the µW regime. The record efficiency reached by this method is demonstrated. An experimental demonstration with a numerical analysis of the line excitation is presented. The spectral analysis of both a point and a line excitation demonstrate that the line excitation spectrum is not only comparable to that of the point excitation, but also extends the range of useful lower frequency content. To further improve the THz efficiency, the line excitation THz array is investigated.en_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectAnnealing dependent electric field distributionen_US
dc.subjectSemi-insulating GaAsen_US
dc.subjectUltrafast opticen_US
dc.subjectOptoelectronic THz sourceen_US
dc.subjectTHz phased arrayen_US
dc.subject.lcshTerahertz technology
dc.subject.lcshOptoelectronics
dc.subject.lcshImaging systems
dc.subject.lcshPhotoconductivity
dc.titleEfficient terahertz photoconductive sourceen_US
dc.typeDissertationen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentElectrical and Computer Engineeringen_US
dc.description.advisorCommittee Chair: Ralph, Stephen; Committee Member: Citrin, David; Committee Member: Cressler, John; Committee Member: Denison, Douglas; Committee Member: Mukhopadhyay,Saibalen_US


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