Plasmonic photoconductive antennas for significant terahertz radiation enhancement

We present a novel photoconductive antenna which utilizes nanoscale plasmonic electrodes to significantly enhance the efficiency and terahertz radiation power of conventional photoconductive antennas. The terahertz radiation power enhancement results from a significant reduction in the average transport path of photocarriers to reach the device contact electrodes. Thus, the photocurrent levels feeding the terahertz antenna in a sub-picosecond timescale are considerably increased, resulting in significantly higher terahertz radiation power levels. By incorporating the nanoscale plasmonic electrodes into a photoconductive antenna, we experimentally demonstrate up to 50 times higher efficiencies and terahertz radiation powers, compared to a similar conventional photoconductive antenna without the plasmonic electrodes.