Optimization design of the diffraction grating profiles based on genetic algorithm

In this paper the rigorous coupled wave analysis (RCWA) was used to analyze the grating diffraction efficiency properties. First, the RCWA must to be improved to avoid instability when the grating period and grating groove depth are relatively large especially for TM mode incident wave. Then the global optimization method-genetic algorithm was used to optimize the grating profile to achieve high diffraction efficiency. Based on the improved RCWA the grating optimal design software(GODS) was developed with the aid of the genetic algorithms (GA). The optimized structure parameters of several typical grating profiles in arbitrary incident angle were given by GODS within short time once the optimal control parameters were selected.