0.84-THz imaging pixel with a lock-in amplifier in CMOS

An 840-GHz Schottky diode detector is integrated with an analog lock-in amplifier in 130-nm bulk CMOS. The integrated lock-in amplifier can support a modulation frequency of up to 10 MHz with a gain of 54 dB, a dynamic range of 42 dB, and an input referred noise of less than 10 nV/√(Hz) at modulation frequencies higher than 100 kHz. The integrated lock-in amplifier occupies an area of 0.17 mm² and consumes 4.9 mA from a 1.2-V supply. The detector and on-chip lock-in amplifier combination was used to form terahertz images.