Abstract-Plasmonic Anti-reflection Coating for Photoconductive Terahertz Generation

Faezeh Fesharaki, Afshin Jooshesh, Vahid Bahrami-Yekta, Mahsa Mahtab, Tom Tiedje, Thomas E. Darcie, and Reuven Gordon

http://pubs.acs.org/doi/abs/10.1021/acsphotonics.7b00410?journalCode=apchd5

Plasmon-enhanced photoconductive antennas allow for improved performance, particularly in below-bandgap absorption devices using low-temperature grown GaAs. Here we design the plasmonic nanostructures to act as anti-reflection coatings as well, achieving below 10% reflection at 1570 nm wavelength in an optimized device. Quantitative agreement is seen between experiment and theory. Terahertz emission field amplitudes demonstrate eighteen times enhancement compared to that of a conventional terahertz photoconductive antenna on the same substrate.