The multi-channel small signal readout system for THz spectroscopy and imaging applications

This paper presents development of the integrated multi-channel readout circuit targeted to support the pixel-line of FET-based THz-detectors. The authors discuss architecture details and design techniques used to address the most important issues related to the processing of very small, low-frequency signals. The effectiveness of the 1/f noise component minimization and crosstalk cancellation, proven by measurements, allows to consider the designed IC as an interesting replacement of the lock-in equipment eliminating the need of THz wave modulation and providing cost-effective multi-channel read-out. Furthermore, due to the high level of miniaturization, proposed solution can be effectively deployed in portable applications. The authors present also the complete measurement system based on this multi-channel ASIC, controlled from the application dedicated to use with NI LabVIEW™ environment.