Development of a high-precision spectrograph for diffraction-limited coronagraphs
Development of a high-precision spectrograph for diffraction-limited coronagraphs
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开发用于衍射极限日冕仪的高精度光谱仪
DOI：
10.1117/12.2629324
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
T.
中科院分区：
文献类型：
--
作者：
Ota;S.;Matsuo;T.;Itoh;S.;Kano;T.; Ikeda;Y.;Kojima;R.;Sukegawa;T.;Nakayasu;T.;Koyama;M.;Sumi;T.;Yamada;T.
可居住候选者的大气特征是寻找太阳系外生命的有效途径之一。然而，由于行星-恒星的通量对比度很高，10-8- 10-10，这就很难了。Itoh & Matsuo（2020）提出的日冕掩模可以抑制宿主恒星光，但受到0.3%的严格波长范围限制。将衍射极限日冕仪与光谱仪相结合的光谱日冕仪有望实现有效带宽的扩大。另一方面，由摄谱仪引起的非公共路径误差可能限制可实现的对比度。我们设计了一台高精度的光谱仪，并测量了它的波前误差。共光路误差为9.9nm RMS，主要是由摄谱仪的凸光栅与球面镜之间的对准误差引起的。从非共程误差测量中估计了光谱日冕的可实现对比度。实验结果表明，在带宽为5%的情况下，可以获得10- 8的对比度，这是一个有希望的结果。
The atmospheric characterization of habitable candidates is one of the effective approaches for search for life out of the solar system. However, it is much hard by high planet-star flux contrast, 10-8- 10-10. A coronagraphic mask proposed by Itoh & Matsuo (2020) can suppress host stellar light but is imposed by a strict wavelength range limit of 0.3%. A spectroscopic coronagraph that combines the diffraction-limited coronagraph with a spectrograph is expected to achieve enlarges the effective bandwidth. On the other hand, a non-common path error, which is induced by the spectrograph, could limit the achievable contrast. We designed a high-accuracy spectrograph motivated for the spectroscopic coronagraph and measured its wavefront error. The common path error is 9.9 nm RMS, which is mostly caused by the alignment error between the convex grating and spherical mirror of the spectrograph. The achievable contrast of the spectroscopic coronagraph was also estimated from the non-common path error measurement. We found that the contrast of 10-8could be achieved with a bandwidth of 5%, which is a promising result as the first step.