Veenendaal Ian, Naylor David, Gom Brad, Christiansen Adam, Jellema Willem, Feenstra Carolien, Ridder Marcel, Eggens Martin, Ade Peter
Department of Physics and Astronomy, University of Lethbridge, 4401 University Dr. W, Lethbridge, Alberta AB T1K 3M4, Canada.
SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands.
Rev Sci Instrum. 2020 Aug 1;91(8):083108. doi: 10.1063/5.0012432.
The sensitivity of state-of-the-art superconducting far-infrared detectors used in conjunction with cryogenically cooled space telescopes and instrumentation is such that spectroscopic observations are generally limited by photon noise from the astronomical source or by galactic foreground or zodiacal emission within the field-of-view. Therefore, an instrument design that restricts the spectral bandpass viewed by the detector must be employed. One method of achieving background limited, high resolution spectroscopy is to combine a high resolution component such as a Fabry-Pérot interferometer (FPI) with a lower resolution, post-dispersing system, such as a grating spectrometer, the latter serving to restrict the spectral bandpass. The resonant wavelength of an FPI is most often tuned by changing the spacing or medium between the parallel reflecting plates of the etalon. In this paper, we present a novel design for an FPI in which the wavelength is tuned by scanning the angle of incidence on a high refractive index etalon. This concept simplifies the cryomechanical design, actuation, and metrology. The first results from the realized instrument are presented and compared with theory. The effects on the spectral response as a function of the incident angle have been simulated and shown to agree well with the observation.
与低温冷却的太空望远镜及仪器配合使用的最先进超导远红外探测器的灵敏度，使得光谱观测通常受限于来自天文源的光子噪声，或视场内的银河前景或黄道光发射。因此，必须采用一种限制探测器所观测光谱带通的仪器设计。实现背景受限的高分辨率光谱学的一种方法是，将高分辨率组件（如法布里 - 珀罗干涉仪（FPI））与较低分辨率的后置色散系统（如光栅光谱仪）相结合，后者用于限制光谱带通。FPI的共振波长最常通过改变标准具平行反射板之间的间距或介质来调谐。在本文中，我们提出了一种新型FPI设计，其中通过扫描高折射率标准具上的入射角来调谐波长。这一概念简化了低温机械设计、驱动和计量。展示了所实现仪器的首批结果并与理论进行了比较。模拟了入射角对光谱响应的影响，结果表明与观测结果吻合良好。
