Friday, January 3, 2014

Mona Jarrehi -High-Performance terahertz optoelectronics based on plasmonic photoconductors

http://web.eecs.umich.edu/~mjarrahi/research.html
Research Highlights
High-performance terahertz optoelectronics based on plasmonic photoconductors
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We demonstrate that use of plasmonic contact electrodes can significantly mitigate the low quantum efficiency performance of photoconductive terahertz optoelectronics. The use of plasmonic contact electrodes offers nanoscale carrier transport path lengths for the majority of photocarriers, increasing the number of collected photocarriers in a sub-picosecond time-scale and, thus, enhancing the optical-to-terahertz conversion efficiency of photoconductive terahertz emitters and the detection sensitivity of photoconductive terahertz detectors. We experimentally demonstrate 50 times higher terahertz radiation powers from a plasmonic photoconductive emitter in comparison with a similar photoconductive emitter with non-plasmonic contact electrodes, as well as 30 times higher terahertz detection sensitivities from a plasmonic photoconductive detector in comparison with a similar photoconductive detector with non-plasmonic contact electrodes. Consequently, our presented plasmonic photoconductive terahertz optoelectronics concept offers more than three orders of magnitude enhancement in the signal-to-noise ratio of time-domain and frequency-domain terahertz spectroscopy and imaging systems.
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