亚波长介质光栅的闪耀特性分析

Blazed Characteristics of Subwavelength Dielectric Grating

采用严格耦合波理论与矩阵LU分解法,求解了亚波长矩形介质光栅的衍射场,给出了TE和TM偏振波的耦合波方程组及其矩阵形式.通过数值计算分析了TE和TM偏振波的入射角、刻槽深度、入射波长等参量对+1级衍射波衍射效率的影响.结果表明,当Λ=0.5λ0,θ=55°,d=0.38λ0,λ=10.6μm时可以实现对TE偏振波+1级的闪耀,衍射效率达到近90%,同时具有较宽广的角度适应范围.

Based on rigorous coupled-wave analysis （RCWA） and the matrix LU decomposition, the diffraction field of rectangular subwavelength dielectric grating was presented. The coupled wave equations and its matrix forms for TE and TM polarization wave were given. The numerical calculus was used to analyze the effects of the first-order diffraction efficiency of the diffracted wave caused by the incident angle,the incident wavelength and the groove depth. It shows that when ∧=0.5λ0,θ=55°,d=0.38λ0 and λ=10.6um, the TE polarization wave blazed in the first-order and the diffraction efficiency achieves approximately 90%. While the TM polarized wave diffraction efficiency of first-order tends 0.