Terahertz heterodyne detection with silicon field-effect transistors

We report on the detection of electromagnetic radiation at 0.65 THz by silicon field-effect transistors operated in heterodyne mode. Aiming at terahertz imaging with numerous pixels in a focal-plane array, we explore the improvement of the dynamic range achieved over power detection when the local-oscillator (LO) power is distributed quasioptically onto all detectors. These consist of resonantly antenna-coupled complementary metal-oxide-semiconductor transistors with a gate length of 0.25 mu m, and each has an integrated voltage amplifier. With a LO power of 2 mu W per detector, the noise-equivalent power amounts to 8 fW/Hz, leading to an estimated improvement of the dynamic range by 29 dB.