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

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.

Read more at:

• C. W. Berry, N. Wang, M. R. Hashemi, M. Unlu, M. Jarrahi, "Significant Performance Enhancement in Photoconductive Terahertz Optoelectronics by Incorporating Plasmonic Contact Electrodes", Nature Communications, 4, 1622, doi: 10.1038/ncomms2638, 2013
• C. W. Berry, M. Jarrahi, "Terahertz generation using plasmonic photoconductive gratings",New Journal of Physics Focus Issue on Terahertz Plasmonics, 14, 105029, 2012
• C. W. Berry, M. Jarrahi, "Principles of impedance matching in photoconductive antennas",Journal of Infrared, Millimeter and Terahertz Waves, 33, 1182-1189, 2012
• C. W. Berry, M. Unlu, M. R. Hashemi, M. Jarrahi, "Use of Plasmonic Gratings for Enhancing the Quantum Efficiency of Photoconductive Terahertz Sources", Proc. International Conference on Infrared, Millimeter, and Terahertz Waves, Wollongong, Australia, Sep 23-28, 2012
• C. W. Berry, M. Jarrahi, "Plasmonic Photoconductive Antennas for High Power Terahertz Generation", Proc. IEEE International Antennas and Propagation Symposium, Chicago, IL, 8-14 July, 2012
• C. W. Berry, M. Jarrahi, "High-Performance Photoconductive Terahertz Sources Based on Nanoscale Contact Electrode Gratings", IEEE International Microwave Symposium Digest, Montreal, Canada, 17-22 June, 2012