Characterization of a proportional-integral-derivative feedback-controlled array of transition-edge sensor-bolometers in a far-infrared double-Fourier interferometry testbed

Double-Fourier interferometry (DFI) from a space-based platform provides a path to achieve broadband imaging spectroscopy in the far infrared with sub-arcsecond angular resolution. To provide further study of the technique and improve its technology readiness, we have constructed a laboratory-based DFI testbed. This instrument is coupled to a custom array of 25 feedback-controlled transition-edge sensor (TES) bolometers. We present the results of characterization experiments to optimize the detector system for laboratory-based experiments involving the DFI testbed. We demonstrate that tuning the proportional-integral-derivative (PID) feedback control loops of the detectors and the timing of the multiplexed measurement process can modify the detector array’s noise performance and speed of response to optical modulation for this purpose. From these, we have determined a set of optimized detector settings that reduce spectral noise in the spatial-spectral interferometer by 37% to 75%. In addition, we present a further thermal characterization of the detector array.