Significant performance enhancement inphotoconductive terahertz optoelectronicsby incorporating plasmonic contact electrodes

摘要

Even though the terahertz spectrum is well suited for chemical identification, materialcharacterization, biological sensing and medical imaging, practical development of theseapplications has been hindered by attributes of existing terahertz optoelectronics. Here wedemonstrate that the use of plasmonic contact electrodes can significantly mitigate the lowquantumefficiency performance of photoconductive terahertz optoelectronics. The use ofplasmonic contact electrodes offers nanoscale carrier transport path lengths for the majorityof photocarriers, increasing the number of collected photocarriers in a subpicosecondtimescale and, thus, enhancing the optical-to-terahertz conversion efficiency of photoconductiveterahertz emitters and the detection sensitivity of photoconductive terahertzdetectors.We experimentally demonstrate 50 times higher terahertz radiation powers from aplasmonic photoconductive emitter in comparison with a similar photoconductive emitterwith non-plasmonic contact electrodes, as well as 30 times higher terahertz detection sensitivitiesfrom a plasmonic photoconductive detector in comparison with a similar photoconductivedetector with non-plasmonic contact electrodes.