Laboratory testing and performance verification of the CHARIS integral field spectrograph
Laboratory testing and performance verification of the CHARIS integral field spectrograph
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CHARIS 积分场摄谱仪的实验室测试和性能验证
DOI：
10.1117/12.2233447
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Masahiko
中科院分区：
文献类型：
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作者：
Groff;Tyler D.; Chilcote;Jeffrey; Kasdin;N. Jeremy; Galvin;Michael; Loomis;Craig; Carr;Michael A.; Brandt;Timothy; Knapp;Gillian; Limbach;Mary Anne; Guyon;Olivier; Jovanovic;Nemanja; McElwain;Michael W.; Takato;Naruhisa; Hayashi;Masahiko
日冕高角分辨率成像光谱仪（CHARIS）是一台为斯巴鲁望远镜建造的积分场光谱仪（IFS）。CHARIS有两种成像模式;高分辨率模式分别是J、H和K波段中的R82、R69和R82，而低分辨率发现模式使用第二低分辨率棱镜，其中R19跨越1.15-2.37微米（J+H+K波段）。发现模式旨在增强斯巴鲁Coronagraphic Extreme Adaptive Optics（SCExAO）自适应光学系统的低内部工作角度，该系统为CHARIS提供Coronagraphic图像。目标是探测和描述棕矮星和热木星行星的特征，其内部工作角低至80毫弧秒，比其母星星暗五个数量级。CHARIS通过光学设计的几个关键方面限制光谱串扰。此外，某些光学部件的对准的可重复性对于数据管道所需的校准至关重要。具体地，小透镜阵列、棱镜和检测器的相对对准必须是高度稳定的并且在成像模式之间是可重复的。我们报告测量的重复性和稳定性，这些机制，测量仪器中的光谱串扰，并通过数据管道传播这些错误。CHARIS的另一个关键设计特征是棱镜，它将氟化钡与大原L-BBH 2高折射率玻璃配对。该棱镜的色散比其他玻璃选择明显更加均匀，CHARIS棱镜代表了第一台使用L-BBH 2作为高折射率材料的近红外天文仪器。这种材料的选择是发现模式实用性的关键，因此在材料的低温表征方面投入了大量精力。详细描述了棱镜组件在其操作环境中的最终性能。光谱仪正在进行最后的校准，低温循环，并将于2016年4月交付给斯巴鲁望远镜。本文是一份关于光谱仪实验室性能的报告，以及它在调试过程中的现状，以便观察者更好地了解仪器的能力。我们还将讨论在测试过程中吸取的经验教训，以及它们对未来用于波前控制的高对比度成像光谱仪的影响。
The Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) is an integral field spectrograph (IFS) that has been built for the Subaru telescope. CHARIS has two imaging modes; the high-resolution mode is R82, R69, and R82 in J, H, and K bands respectively while the low-resolution discovery mode uses a second low-resolution prism with R19 spanning 1.15-2.37 microns (J+H+K bands). The discovery mode is meant to augment the low inner working angle of the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) adaptive optics system, which feeds CHARIS a coronagraphic image. The goal is to detect and characterize brown dwarfs and hot Jovian planets down to contrasts five orders of magnitude dimmer than their parent star at an inner working angle as low as 80 milliarcseconds. CHARIS constrains spectral crosstalk through several key aspects of the optical design. Additionally, the repeatability of alignment of certain optical components is critical to the calibrations required for the data pipeline. Specifically, the relative alignment of the lenslet array, prism, and detector must be highly stable and repeatable between imaging modes. We report on the measured repeatability and stability of these mechanisms, measurements of spectral crosstalk in the instrument, and the propagation of these errors through the data pipeline. Another key design feature of CHARIS is the prism, which pairs Barium Fluoride with Ohara L-BBH2 high index glass. The dispersion of the prism is significantly more uniform than other glass choices, and the CHARIS prisms represent the first NIR astronomical instrument that uses L-BBH2 as the high index material. This material choice was key to the utility of the discovery mode, so significant efforts were put into cryogenic characterization of the material. The final performance of the prism assemblies in their operating environment is described in detail. The spectrograph is going through final alignment, cryogenic cycling, and is being delivered to the Subaru telescope in April 2016. This paper is a report on the laboratory performance of the spectrograph, and its current status in the commissioning process so that observers will better understand the instrument capabilities. We will also discuss the lessons learned during the testing process and their impact on future high-contrast imaging spectrographs for wavefront control.