共光路干涉型天文光谱探测技术研究

It is one of the hotspots in astronomy research to search for Extraterrestrial Intelligence，and answer the question of whether human being alone is lonely in the universe. Astronomers need larger telescopes and spectrograph instruments with higher spectral efficiency. The traditional dispersive spectrograph limits its application on the telescope because of the efficiency and manufacturing cost of the grating. Therefore, this study will explore the feasibility of applying the Sagnac triangle optical interferometric spectrometer to the Astronomical Spectral observation. In theory, the analysis model of the Sagnac optical interference spectrometer will be set up, and the experimental device for the interference spectrometer of the Sagnac common optical path structure is set up. Measuring the spectra of the flat field lamp and calibration light, to analyze and verify the performance of Sagnac common path of spatial modulated interferometer; finally, with a small telescope that will clearly verify the performance of the scientific observation . The technology uses the common path structure, and also has the advantages of high stability, high throughput, high spectral resolution and wide spectral range. It is expected to be applied to the spectral observation of the very large telescope aperture .

搜寻系外文明的存在，回答人类在宇宙是否孤独的问题是天文学研究的热点之一。天文学家需要更大口径的望远镜和更高光谱效率的光谱仪仪器。传统色散型光谱仪因光栅效率和制造成本限制了其在极大望远镜上的应用。为此，本研究将探索Sagnac型三角共光路干涉型光谱仪应用于天文光谱观测的可行性。理论上建立Sagnac共光路干涉型光谱仪的分析模型，搭建Sagnac型共光路结构的干涉光谱仪的实验装置。实验测量平场灯和定标灯的光谱，分析和验证Sagnac型共光路干涉空间调制干涉光谱仪的性能;最后与小型望远镜对接对星观测验证其性能。该技术采用共光路结构，系统稳定性高，同时兼具高通量、高光谱分辨率和宽光谱范围的优点，有望应用于极大口径望远镜的光谱观测。

传统的天文光谱仪器以色散型为主，多采用光栅或棱栅实现科学目标的色散，色散型光栅因为入射狭缝的限制和光栅衍射角的限制，色散型光谱仪通光效率较低，光谱覆盖范围窄。此外随着望远镜口径的增大，在满足同等光谱分辨率要求，光谱仪的准直口径和光栅的口径都增加，需要更大口径的透射材料和衍射光栅。虽然光栅拼接的方法能在一定程度上满足光栅尺寸的要求，但设计与制造成本显著增加。为了弥补色散型光谱仪的缺陷，满足科学观测的需要，发展新一代的光谱测量方法，研究高通量、高光谱分辨率同时兼具宽光谱动态范围的光谱观测技术势在必行，本课题建立基于Sagnac三角共光路干涉的傅立叶变换光谱仪的理论分析模型和数值模拟程序。理论结合仿真模拟分析Sagnac型干涉光谱仪的光谱调制度、光谱分辨率、光谱覆盖范围和信噪比参数指标是否能满足天文光谱的需求，以及影响这些性能的主要因素，同时搭建了基于Sagnac横向剪切器共光路干涉的空间调制型干涉光谱仪的实验装置，实验测试了Sagnac型干涉光谱分辨率、光谱覆盖范围、光谱调制度和信噪比参数，对比验证该技术用于天文光谱观测的可行性。认为 Sagnac 型三角共光路傅里叶变换光谱仪可有效用于空间天文光谱观测。