Investigation on the Influence of Macro-micro Grating Parameters on Diffraction Characteristics through FDTD Simulation

The grating is the displacement measurement standard, and the diffraction efficiency of the diffracted light of the grating mainly determines the accuracy of the displacement measurement system. In this work, through three-dimensional finite-difference time-domain (FDTD) method simulation, the diffraction efficiency of the ±1 ^st order diffracted light of the transmission diffraction grating under different macro complex groove types and micro surface roughness is studied, and the optimal groove type and surface roughness parameters were obtained. The research results provide a basis for the optimal design of grating manufacturing.