标题： EUCLID NISP光栅飞行模型性能 显示英文标题

标题： The EUCLID NISP grisms flight models performance

摘要： ESA欧几里得任务将于2020年发射，以了解导致宇宙加速膨胀的暗能量的本质，并绘制暗物质的几何结构。该地图将通过两个仪器：NISP和VIS来研究距离红移关系和宇宙结构的演化。NISP（近红外光谱-光度计）在近红外光谱范围（0.9-2$\mu$m）内工作，具有两种观测模式：光度模式用于获取宽带滤光片的图像，光谱模式用于在探测器上获取无狭缝分散的图像。光谱模式使用四个低分辨率光栅棱镜来覆盖两个光谱范围：三个“红色”光栅棱镜用于1250-1850nm范围，具有三种不同的方向，一个“蓝色”光栅棱镜用于920-1300nm范围。NISP光栅棱镜是复杂的光学组件，结合了四种主要光学功能：光栅棱镜功能（由光栅在棱镜斜边上的衍射第一级实现色散而不产生光束偏转），由沉积在棱镜第一面上的多层滤光片实现的光谱滤光功能，由棱镜弯曲的滤光片面实现的聚焦功能（曲率半径为10m），以及由光栅实现的光谱波前校正功能，其刻线路径既不平行也不直线。这些组件的开发已在马赛天体物理实验室（LAM）进行了10年，并与项目阶段相关：已开发了原型以证明可行性，然后是工程和合格模型以验证组件的光学和机械性能，最后制造并测试了飞行模型，并将安装在NISP仪器上。在本文中，我们介绍了在LAM表征的四个欧几里得NISP光栅棱镜飞行模型的光学性能：波前误差、光谱透过率和光栅刻线轮廓。描述了用于这些特定光学组件表征的测试设备和方法。测试结果的分析表明，NISP的光栅棱镜飞行模型符合规格，光谱带宽内的效率优于70%，表面波前误差优于30nm RMS。这些组件经受住了高达11.6g RMS随机测试的振动合格水平和降至130K的真空低温测试，并在透射状态下测量了光学质量。在LAM完成测试活动后，欧几里得光栅棱镜飞行模型于2017年11月交付给NISP项目，该活动已证明符合规格。 显示英文摘要

摘要： ESA EUCLID mission will be launched in 2020 to understand the nature of the dark energy responsible of the accelerated expansion of the Universe and to map the geometry of the dark matter. The map will investigate the distanceredshift relationship and the evolution of cosmic structures thanks to two instruments: the NISP and the VIS. The NISP (Near Infrared Spectro-Photometer) is operating in the near-IR spectral range (0.9-2$\mu$m) with two observing modes: the photometric mode for the acquisition of images with broad band filters, and the spectroscopic mode for the acquisition of slitless dispersed images on the detectors. The spectroscopic mode uses four low resolution grisms to cover two spectral ranges: three ''red'' grisms for 1250-1850nm range, with three different orientations, and one ''blue'' grism for 920- 1300nm range. The NISP grisms are complex optical components combining four main optical functions: a grism function (dispersion without beam deviation of the first diffracted order) done by the grating on the prism hypotenuse, a spectral filter done by a multilayer filter deposited on the first face of the prism to select the spectral bandpass, a focus function done by the curved filter face of the prism (curvature radius of 10m) and a spectral wavefront correction done by the grating which grooves paths are nor parallel, neither straight. The development of these components have been started since 10 years at the Laboratoire d'Astrophysique de Marseille (LAM) and was linked to the project phases: prototypes have been developed to demonstrate the feasibility, then engineering and qualification models to validate the optical and mechanical performance of the component, finally the flight models have been manufactured and tested and will be installed on NISP instrument. In this paper, we present the optical performance of the four EUCLID NISP grisms flight models characterized at LAM: wavefront error, spectral transmission and grating groove profiles. The test devices and the methods developed for the characterization of these specific optical components are described. The analysis of the test results have shown that the grisms flight models for NISP are within specifications with an efficiency better than 70% on the spectral bandpass and a wavefront error on surfaces better than 30nm RMS. The components have withstood vibration qualification level up to 11.6g RMS in random test and vacuum cryogenics test down to 130K with measurement of optical quality in transmission. The EUCLID grisms flight models have been delivered to NISP project in November 2017 after the test campaign done at LAM that has demonstrated the compliance to the specifications.