We report on Terahertz (THz) detectors based on III-V high-electron-mobility field-effect transistors (FET). The detection results from a rectification process that is still highly efficient far above frequencies where the transistor provides gain. Several detector layouts have been optimized for specific applications at room temperature: we show a broadband detector layout, where the rectifying FET is coupled to a broadband logarithmic-periodic antenna. Another layout is optimized for mixing of two orthogonal THz beams at 370 GHz or, alternatively, 570 GHz. A third version uses a large array of FETs with very low access resistance allowing for detection of very short high-power THz pulses. We reached a time resolution of 20 ps.
We previously reported resonant photovoltaic terahertz detection via bulk plasmons in GaAs field-effect-transistors
(FETs). Here, we introduce a device model which incorporates the microscopic dynamics of terahertz-field-driven
electrons in the FET channel, resonant excitation of three dimensional (bulk) plasmons, and self-mixing theory of
Lisauskas and Pfeiffer. The resulting model can simulate our experimental results and implies a bulk plasmon-assisted
terahertz self-mixing process occurs in the FET-based terahertz detectors. The model also suggests three factors are
important to improving the device performance – power coupling efficiency, self-mixing efficiency, and resonance with