Development of a cryogenic far-infrared post-dispersed polarizing Fourier transform spectrometer
Abstract
Scientists must reconsider the design of cryogenically cooled spectrometers in order to fully exploit the ever-increasing sensitivity of superconducting far-infrared bolometers. While Fourier transform spectrometers (FTS) have an illustrious history in astronomical research, the sensitivity of modern detectors is such that the multiplex disadvantage of FTS is prohibitive unless the spectral bandpass can be restricted to a few tenths of one percent. One method of achieving this goal is to use a diffraction grating as a post-dispersing component. Unlike a typical FTS, in which a single detector simultaneously measures a broad spectral band, a post-dispersed detection system requires multiple detectors, each with their own unique spectral, spatial and temporal responses. Moreover, the narrow spectral band viewed by each detector results in an interferogram having a large coherence length. In general, the signal is heavily modulated, yet truncated. While simulations play a useful role in modeling instrumental performance, there is no substitute for data obtained from a real implementation of an instrument concept. In this paper we describe the development of a cryogenic, far-infrared, post-dispersed, polarizing FTS (PDPFTS). The end-to-end performance of the PDPFTS will be evaluated in a large cryogenic test facility to simulate a space environment. The results provide valuable insight into the spectral calibration and data processing challenges that will be faced by hybrid spectrometers employing a post-dispersed component.
- Publication:
-
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI
- Pub Date:
- August 2022
- DOI:
- 10.1117/12.2629570
- Bibcode:
- 2022SPIE12190E..0RN