偏振干涉成像光谱技术以傅里叶变换光谱学为理论基础, 以一系列起偏/检骗器、 剪切分束器和延时晶体等双折射晶体材料为主要结构, 较之传统光栅式色散型光谱仪具有多通道、 图谱合一、 大光通量、 高信噪比和抗环境振动干扰等一系列优点, 并且结合多普勒光谱学相关原理和技术, 已被广泛应用在各种天文学和天体物理学测试与计量领域如空间遥感、 视向速度、 宇航飞行、 月球探测等。 但是许多前人研究工作中仍然存在两个尚未妥善解决的问题: (1) 视场受限。 普通型偏振干涉成像光谱仪存在远场条纹的弯曲而使系统视场角限制在±2°以内, 严重影响傅里叶变换后的光谱重构精度; (2) 相位热漂移。 晶体的热胀冷缩和双折射率之差随温度变化的特性导致像面干涉条纹发生随机抖动误差, 将严重影响以多普勒频移为原理的视向速度等测量精度。 因此, 首先引入一块半波片构成增强型的Savart剪切分束器实现主动的视场展宽, 可以使增强后的观察视场角达到±10°左右。 这一改进不仅提高了傅里叶光谱变换的算法精度, 同时也大幅增加光通量从而实现对微光光谱进行高信噪比的探测与标定。 另外, 为了消除环境温度造成的相位热漂移误差, 选用偏硼酸钡（α-BBO）和铌酸锂（LiNbO3）两种晶体进行精密组合匹配。 该关键技术利用这两种晶体的双折射率之差随温度变化的相反特性, 从而实现相位热漂移误差补偿。 实验证明, 在实验室环境温度下热相位漂移误差不超过0.02 rad。 通过这些方案改善偏振干涉成像光谱仪的测试精度, 拟实现对天文光梳以及其他大型天文光谱仪器快速而精确的标定与测试。

The Polarized Interference Imaging Spectrometer (PIIS), which is based on the theory of Fourier Transform Spectroscopy, is consisted of a series of birefringent crystals such as polarizers, a beam splitter as well as various lengths of birefringent crystals required to achieve large delays. The PIIS, compared with a traditional grating-based dispersion spectrometer, has various advantages of multiple-channel measurements, simultaneous information acquisition of both original images and fringes containing spectral details, large light flux, better light signal-to-noise ratio (SNR) as well as anti-vibration etc. Therefore, the PIIS has also been developed in a range of astronomy and astrophysics areas such as remote sensing, extrasolar planet radial velocity measurements, spacecraft design, lunar exploration etc. However, by reviewing of former works and references, two major drawbacks still remain in PIIS and need to be fixed. For one thing, the classic PIIS has a very limited field-of-view (FOV) around ±2°, which means the acquired fringes on the image plane will show quite strong non-linear distortion and hence degrade the accuracy of spectral reconstruction via Fourier transform. For another, the random thermal-phase-drift (TPD), given rise from both thermal expansion and birefringence variation caused by the environmental temperature fluctuation, has barely been studied before and will inevitably result in extra radial velocity error based on Doppler Spectroscopy. In this paper, a noble polarization interference imaging spectrometer with the emphasis on the FOV widening technology is introduced. This technology, using a compensated Savart plate containing a half-wave plate sandwiched between two orthogonally placed displacer plates as a compensated Savart plate, produces an angle-dependent phase shear to create parallel spatial interference fringes with a FOV around ±10°. This improvement not only enhances the accuracy of Fourier Transform algorithm but also increases input luminous flux and therefore even weak input spectrum detection and calibration results with high SNR can be fully accomplished. Also, a secondary set of birefringent plates (α-BBO and LiNbO3) with opposite thermal properties is proposed to passively diminish TPD caused by temperature fluctuation. The experiment shows that thermal-drift-phase error is perfectly restricted within 0.02 rad in the laboratory environment. As a consequence, this advanced PIIS is eligible to realize the fast and accurate measurement and calibration application in the field of large astronomical spectral instruments with ultra-high spectral resolution occasions such as Astronomical Frequency Comb.