一种非偏振高衍射效率透射光栅的设计与制作  

Design and Fabrication of a Non⁃Polarized Transmission Grating with High Diffraction Efficiency

作　　者：于良成 陆凡凡 李时洋 孙满满 邱克强 Yu Liangcheng;Lu Fanfan;Li Shiyang;Sun Manman;Qiu Keqiang(National Synchrotron Radiation Laboratory,University of Science and Technology of China,Hefei 230000,Anhui,China)

机构地区：[1]中国科学技术大学国家同步辐射实验室,安徽合肥230000

出　　处：《光学学报》2024年第20期9-19,共11页Acta Optica Sinica

基　　金：国家重点研发计划(2021YFB3203102)。

摘　　要：表面浮雕(SR)光栅是光学天文望远镜系统中摄谱仪的核心分光元件,它的材料稳定、偏振灵敏度更低且可以提供更高的衍射效率以及更大的带宽。本文设计并制作了一种工作在630~680 nm波段的非偏振、高效率封装透射光栅,使用模态法结合有限元计算方法对比了封装光栅与熔石英透射光栅的效率,并得到封装光栅的最佳参数和工艺容差。使用全息-离子束刻蚀工艺成功制备了几块60 mm×60 mm的封装光栅,测试结果表明,在工作波段内,该封装光栅非偏振-1级峰值衍射效率约为91%,衍射效率大于85%的带宽为37 nm,偏振灵敏度低于7%。实验结果与模拟结果有良好的一致性。Objective Spectroscopy is a technique for measuring light intensity across ultraviolet,visible,nearinfrared,and infrared bands.In astronomical telescope systems,spectrographs operating in the visible light band enable the study of individual stars in neighboring galaxies,exoplanets in the Milky Way,black holes,and neutron stars.The core component of a spectrograph is the diffraction grating,which should possess high diffraction efficiency,wide bandwidth,and low polarization sensitivity.Current diffraction gratings used in large astronomical telescopes include volume phase holographic gratings(VPHGs)and surface relief gratings(SRGs).While VPHGs offer compact design and high diffraction efficiency,they are significantly affected by environmental factors such as temperature and humidity.They also have limitations such as narrow bandwidth,reduced efficiency in nonpolarized modes,and complex fabrication processes.To address these issues,we design and fabricate a stable fused silica encapsulated grating that exhibits high diffraction efficiency and low polarization sensitivity for spectral detection in the visible light band.Methods For the design and fabrication of encapsulated gratings,we first use the modal method to determine the optimal grating groove depth and duty cycle.We then design an antireflective film,model the encapsulated grating structure using finite element software,and calculate the diffraction efficiency and polarization sensitivity of the optimal structure.A TiO2 material encapsulated grating is fabricated using holographic ion beam etching combined with atomic layer deposition coating technology.Finally,we conduct efficiency testing on the encapsulated grating,using finite element software to model the actual morphology and calculate the theoretical diffraction efficiency,comparing these results with experimental data to analyze error sources.Results and Discussions We propose a fused silica encapsulated grating for visible light spectral observation that offers high diffraction efficiency,low pol

关 键 词：衍射光栅 非偏振 模态法 全息-离子束刻蚀 衍射效率 

分 类 号：O436[机械工程—光学工程]