Compact Remote Spectral Terahertz Imager

Abstract

We report on development of an array of spectral sensitive detectors cooled down to 70 K by the compact cryocooler. The spectral sensitive operation of the detectors, explored between 0.16 THz and 0.22 THz, is due to the resonant excitation of the plasma waves in the two-dimensional electron gas of GaAs/AlGaAs heterostructure. A typical responsivity of the detectors is 0.01 A/W at 70 K while it increases by two orders of magnitude when the detector array is cooled down to 0.5 K. The photo-response has surprisingly a narrow peak of spectral sensitivity, $$\sim$$ ∼ 2–5%, which are highly likely due to the dimensional resonances of the plasma waves. As a demonstration of the spectral sensitive operation we detect a spectral feature of LiNbO$$_{3}$$ 3 crystal at 0.174 THz.