Design and analysis of anti-reflection subwavelength structured gratings with operating wavelength of 1064nm

Abstract

Subwavelength structured gratings are increasingly used in new optoelectronic devices, micro-optical electromechanical systems, and other fields due to their functional diversity and large design freedom. When the characteristic size of the structure is much smaller than the wavelength of the incident light, only zero-order reflection and transmission diffraction will exist. By changing the parameter values of column width, duty cycle, and trench depth of the subwavelength structured grating, its reflectivity can be changed. In this paper, the finite difference time domain method (FDTD) and the equivalent medium theory are used to study and analyze the influence of the subwavelength structural parameters of the grating on the reflection characteristics and design an anti-reflection subwavelength structural grating with an operating wavelength of 1064nm. The simulation results show that when the grating period is 0.4μm, the duty cycle is 0.875, the groove depth is 0.23μm, and the column width is 0.35μm, the reflectivity of the subwavelength structure grating for incident light from 0° to 30° can reach 0.5%~0.7%.