Novel Devices and Components for THz Systems
WRIGHT STATE UNIV DAYTON OH
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First, this work will present a novel ErAsGaAs photoconductive switch used to make a THz source excited by 1550 nm laser pulses. It will be shown that the excitation process taking place in the material relies on extrinsic rather than intrinsic photoconductivity. Then, several experiments will be presented that aim to improve the efficiency of the device and further the understanding of the underlying physical mechanisms. The erbium composition of the photoconductive layer will be varied and the effects of these variations on THz generation will be investigated. Then the wavelength of the drive laser used to excite the extrinsic photoconductive mechanism will be varied, while recording the photocurrent responsivity. This wavelength study will be used to find the optimal drive wavelength for maximum THz power. In conclusion, the results of these experiments will show that extrinsic PC THz generation is practical, cost effective, and capable of producing an average THz power of more than 100 microns W. Photoconductive antennas are mostly used to conduct spectroscopy measurements, either in time domain systems TDS or in frequency domain systems FDS. Currently, both techniques can reach high-frequencies greater than 1 THz but struggle to do so while making fast, high-resolution measurements greater than 2 GHz. In addition, both methods can be time consuming to set up and perform. A superior spectrum analysis technique would greatly facilitate THz application development by making results easier and less expensive to obtain. Therefore, the second part of this dissertation addresses the need for quicker and more precise THz spectrum analysis by demonstrating a new type of THz spectrum analyzer based on a high-speed, tunable, Fabry-Perot interferometer.
- Electrooptical and Optoelectronic Devices
- Atomic and Molecular Physics and Spectroscopy