A high sensitivity terahertz detector tunable over a very large frequency range

A high sensitivity terahertz detector is one of the key components for a high resolution terahertz spectrometer or imager. Earlier we have demonstrated a terahertz detector that is tunable over the frequency range from 100 GHz to 1.4 THz. Based on a metal-semiconductor field-effect-transistor (MESFET) and a dipole-antenna, the detector had a sensitivity slightly poorer than 10\textasciicircum -9 W/(Hz)\textasciicircum 1/2 in terms of noise-equivalent-power (NEP). In order to increase the sensitivity and the tuning frequency range, we have modified the MESFET structure and also replaced the dipole antenna with a spiral antenna. Our computer simulations show that the new detector can have a sensitivity much better than 10\textasciicircum -9 W/(Hz)\textasciicircum 1/2 and its frequency tuning range can be from 100 GHz to over 3 THz. We will report details of the design parameters, computer simulations, and experimental results.