高衍射效率低偏振灵敏度全反射浸没光栅的设计  

Design of Total Internal Reflection Immersed Gratings with High Diffraction Efficiency and Low Polarization Sensitivity

作　　者：陈慧盈 陈新华 潘俏[1,2,3] 朱嘉诚 沈为民 Chen Huiying;Chen Xinhua;Pan Qiao;Zhu Jiacheng;Shen Weimin(School of Optoelectronic Science and Engineering,Soochow University,Suzhou 215006,Jiangsu,China;Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province,Suzhou 215006,Jiangsu,China;Key Lab of Modern Optical Technologies of Education Ministry of China,Suzhou 215006,Jiangsu,China)

机构地区：[1]苏州大学光电科学与工程学院,江苏苏州215006 [2]江苏省先进光学制造技术重点实验室,江苏苏州215006 [3]教育部现代光学技术重点实验室,江苏苏州215006

出　　处：《光学学报》2023年第22期72-79,共8页Acta Optica Sinica

基　　金：国家自然科学基金(62105230);江苏高校优势学科建设工程(PAPD);苏州市产业前瞻与关键核心技术项目(SYC2022142)。

摘　　要：浸没光栅是星载温室气体监测成像光谱仪光学系统中的核心分光元件,能够实现更高的光谱分辨率和更紧凑的结构尺寸。推导了浸没光栅的色散率公式,并对比了采用浸没光栅和普通平面光栅时的光谱分辨率。针对温室气体O2-A带的探测需求,利用有限元计算方法开展了浸没光栅槽形结构的优化设计,得到了兼有高衍射效率和低偏振灵敏度的全反射型浸没光栅槽形参数,并分析了光栅结构参数和等效介质层的制造公差。设计结果表明,在750~770 nm波段范围内,该浸没光栅-1级平均衍射效率高于92%,偏振灵敏度低于1%。Objective The concentration of greenhouse gases in the earth's atmosphere is increasing year by year under the influence of fuel burning,deforestation,and industrial development.The continuous emission of greenhouse gases will result in increased global temperature and extreme weather such as heavy rainfall and sea level rise.Remote sensing of greenhouse gases is an important method for tracking greenhouse gas emissions and understanding the earth's climate evolution.As one of the most important optical payloads for spaceborne greenhouse gas monitoring,the grating imaging spectrometer features high resolution,high signal-to-noise ratio,and nearly linear dispersion.The immersed grating can achieve higher spectral resolution and more compact structural size and has been employed as the dispersion elements in imaging spectrometer for remote sensing of greenhouse gases.Currently,immersed gratings with higher performance are required to fulfill the requirements for more accurate greenhouse gas monitoring.For conventional reflective immersed gratings,metallic coatings are adopted to reflect the incident light.However,there are many disadvantages for the metallic coating.Firstly,this coating may cause resonance absorption due to the plasmon effect.The resonance absorption will decrease the diffraction efficiency and increase the polarization sensitivity of the grating.Secondly,it is difficult to deposit metal materials on the grating groove,which will also cause decreased diffraction efficiency.To this end,we propose and design a total internal reflection immersed grating whose grating groove is coated with nano laminate.It has high diffraction efficiency and low polarization sensitivity and can be utilized in the O2-A channel for the imaging spectrometer of greenhouse gas monitoring.Methods According to the monitoring requirements of greenhouse gases,the design of the immersed grating is as follows.Firstly,the grating structure is modeled by the finite element software,and the diffraction efficiency and polarization se

关 键 词：衍射光栅 浸没光栅 全反射 等效介质层 衍射效率 偏振灵敏度 

分 类 号：TH744[机械工程—光学工程]