亚波长抗反射光栅结构的设计及制备

Design and Fabrication of Subwavelength Anti-Reflection Grating Structure

针对现有亚波长抗反射光栅结构参数对加工工艺要求较高且难以制备等问题,设计了一种方柱形二维抗反射光栅结构。依据等效介质理论和薄膜增透理论对亚波长抗反射光栅结构参数进行仿真分析,结果表明其透射率在远红外波段20~24μm平均透射率能够达到98%,中心波段21.8μm处透射率达到99%。使用飞秒激光直写方式进行实验制备,测得平均透射率达77%,中心波段透射率达到77%,与仿真结果相近。经实验验证,所设计的亚波长光栅结构的工艺容差较现有光栅结构更好,且对实验加工精度要求较低,为其他类似光栅结构的设计和加工提供了新的思路。

In view of the problems that the existing sub-wavelength anti-reflection grating structure parameters have high requirements on processing technology and are difficult to manufacture,a square cylindrical two-dimensional anti-reflection grating structure is designed.Based on the equivalent medium theory and thin-film anti-reflection theory,the structural parameters of the subwavelength anti-reflection grating are simulated and analyzed.The results show that the average transmittance of the far-infrared band at 20~24μm can reach 98%,and the transmittance at the central band of 21.8μm reaches 98%.99%.The femtosecond laser direct writing method was used for experimental preparation,and the measured average transmittance reached 77%,and the central band transmittance reached 77%,which was similar to the simulation result.It is verified by experiments that the process tolerance of the subwavelength grating structure designed in this paper is better than that of the existing grating structure,and the requirements for experimental processing accuracy are lower,which provides a new way of thinking for the design and processing of other similar grating structures.