Enhanced performance of resonant sub-terahertz detection in a plasmonic cavity

Abstract

A multi-gate high electron mobility transistor coupled to a log-periodic antenna was engineered to detect sub-terahertz radiation through resonant excitation of plasmon modes in the channel. The device was integrated with a silicon hyper-hemispherical lens in order to enhance radiation collection and eliminate parasitic substrate modes. The continuous detector response spectrum from 185 GHz to 380 GHz indicates the presence of distinct collective plasmonic cavity modes resulting from the quantization of the plasmon wavevector. In a bolometric detection mode, a noise equivalent power of less than 50 pW/Hz1/2 and a responsivity exceeding 100 kV/W have been measured at 11.5 K.