中国计量学院 光学与电子科技学院, 杭州 310018
利用严格傅里叶模式理论研究了不同基底折射率、入射角度、归一化周期、归一化沟槽深度对正弦型光栅微结构衍射效率的影响, 并分析了该光栅的衍射特性.基于标量衍射理论和等效介质理论, 分别计算了光栅周期远远大于和远远小于入射波长时, 正弦型光栅的衍射效率, 并与傅里叶模式理论的计算结果进行比较, 分析标量衍射理论和等效介质理论的有效性.结果表明：在垂直入射条件下, 当光栅基质材料折射率为1.5时, 标量衍射理论在光栅归一化周期大于5时, 能够准确计算光栅衍射效率, 误差小于3%; 当基底折射率增大到3.42时, 只有在光栅归一化周期大于10时, 标量衍射理论才有效, 误差小于5%; 当正弦型光栅透射光中只有0级衍射光传播时, 等效介质理论能够准确计算其透射率; 随着入射角度的增大, 标量衍射理论和等效介质理论的有效性都不同程度地降低.
衍射元件 亚波长器件 傅里叶模式方法 正弦型光栅 等效介质理论 标量衍射理论 Diffraction element Subwavelength component Fourier modal method Sinusoidal grating Effective medium theory Scalar diffraction theory 光子学报
2016, 45(7): 070705001
Author Affiliations
Abstract
1 Key Laboratory of Material Science and Technology for High Power Lasers, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China
A new design of shallow-etched multilayer dielectric grating (MDG) exhibiting a diffraction efficiency (DE) of approximately 100% in the –1st order at 1064-nm wavelength in Littrow mounting is reported. Particle swarm optimization algorithm and Fourier modal method are used to design MDG and calculate the DE of MDG. The thickness of the grating layer is less than 80 nm which is much shallower than that in the currently reported MDG design for a high DE, which is greatly helpful for the MDG etching process. Meanwhile, the bandwidth of DE which is more than 97.5% of MDG is 60 nm, and it is a meaningful result for MDG to be used in ultrashort pulse compression system.
多层介质膜光栅 浅刻蚀 粒子群优化算法 傅里叶模式方法 050.0050 Diffraction and gratings 050.1940 Diffraction 050.1950 Diffraction gratings 050.2770 Gratings 310.0310 Thin films Chinese Optics Letters
2010, 8(s1): 29
