Field-Effect Transistor-Based Detector for Hyperspectral THz Imaging

In this paper, we show experimental evidence of applicability of a field-effect transistor-based THz detector (TeraFET) for the simultaneous hyperspectral raster scanning imaging. For this work, we have used a dual frequency comb setup extended to THz frequencies, as well as a TeraFET detector adopted for a high frequency readout circuit. Such a spectroscopic imaging system can acquire simultaneously many frequency lines with outstanding frequency accuracy and adjustable frequency resolution even at very low THz source power. The dual frequency comb THz system is also capable of narrow linewidth, which makes spectroscopy measurements with high resolution more feasible. The TeraFET detector has optical NEP below 19 pW/Hz^0.5 at 296 GHz. Additionally, the detector was supplemented with a low-noise amplifier of 40.8 dB gain and 200 kHz 3-dB bandwidth.