CMOS detector arrays in a virtual 10-kilopixel camera for coherent terahertz real-time imaging

We demonstrate the principle applicability of antenna-coupled complementary metal oxide semiconductor (CMOS) field-effect transistor arrays as cameras for real-time coherent imaging at 591.4 GHz. By scanning a few detectors across the image plane, we synthesize a focal-plane array of 100 x 100 pixels with an active area of 20 x 20 mm(2), which is applied to imaging in transmission and reflection geometries. Individual detector pixels exhibit a voltage conversion loss of 24 dB and a noise figure of 41 dB for 16 mu W of the local oscillator (LO) drive. For object illumination, we use a radio-frequency (RF) source with 432 mu W at 590 GHz. Coherent detection is realized by quasioptical superposition of the image and the LO beam with 247 mu W. At an effective frame rate of 17 Hz, we achieve a maximum dynamic range of 30 dB in the center of the image and more than 20 dB within a disk of 18 mm diameter. The system has been used for surface reconstruction resolving a height difference in the mu m range. (C) 2012 Optical Society of America