为解决光学系统中普遍存在的菲涅耳反射问题，提高光的透射率，设计了一种二维矩形SiO2光子晶体结构光栅。采用勒让德多项式展开法对该结构在可见-近红外波长范围入射光波的透射率进行了模拟计算，寻找到了合适的占空比e、光栅深度h和基底厚度d，使得光栅的透射率在入射角为0～60°范围内、入射波长在400 nm～1 200 nm范围内变化时，其透射率的变化相对稳定，透射率的平均值可达到96%以上。

In order to improve the light transmittance and solve the Fresnel reflection problem which is common in optical systems, we designed a two-dimensional rectangular SiO2 photonic crystal surface grating structure. Using the Legendre polynomial expansion method to calculate the transmittance in the visible-near infrared wavelength range of the incident light wave of the structure, we found the appropriate duty cycle e, the grating depth h, and the substrate thickness d, which could stabilize the change of transmission rate and make the average rate reach over 96% when the incident angle varied in the range of 0～60° and the incident wave length in the range of 400 nm～1200 nm.