A Flexible Phase-Insensitive System for Broadband CW-Terahertz Spectroscopy and Imaging

We present a compact, robust, and flexible continuous-wave (CW) terahertz system, ideally suited for both imaging and high-resolution broadband spectroscopy. The setup employs an incoherent detection scheme: A photomixer transmitter is combined with a zero-bias Schottky diode on the receiver side. The useable bandwidth extends to 1500 GHz, with a spectral resolution on the 10 MHz level. In proof-of-principle measurements, we apply our setup to imaging of objects within a paper envelope as well as transmission and reflection-mode spectroscopy, taking advantage of the high spectral resolution of the terahertz source and the broad bandwidth and efficiency of the Schottky receiver.