Design considerations and performance metrics of a high-sensitivity multi-band terahertz linear camera

This paper reports on the design and performance of a terahertz (THz) linear camera with 50 pW/√Hz noise-equivalent power (NEP). This camera is sensitive to four bands of vertically and horizontally polarized THz radiation (0.22, 0.32, 0.42, and 0.52 THz). The heart of the camera is a diode-based focal plane array (FPA) that has a 10 nV thermal noise level and 1-2 kV/W sensitivity across the four bands. The amplifier chain is capable of amplifying with a gain of up to 20,000, which gives the system the ability to detect signals of approximately 30-50 nV. A 12 bit analog-to-digital converter (ADC) and real-time digital signal processing provides signal recovery and processing at an application level with fast (20 kHz) frame rates.