Grating Analysis and Optimization

Optimization of slanted grating parameters for the high-efficient incoupling purpose. Starting from a rectangular grating, by keeping the grating period and varying the slant angle, fill factor, and grating height, an efficiency over 90% for the first diffraction order is obtained. Within the optimization, rigorous FMM/RCWA is applied for the calculation of diffraction efficiencies. Optimization of slanted grating parameters for the high-efficient incoupling purpose. Starting from a rectangular grating, by keeping the grating period and varying the slant angle, fill factor, and grating height, an efficiency over 90% for the first diffraction order is obtained. Within the optimization, rigorous FMM/RCWA is applied for the calculation of diffraction efficiencies. Picture: IAP, F.Wyrowski

Gratings as well as other micro- and nanostructures are shown to be of great importance in modern optics. In field tracing, the rigorous Fourier modal method (FMM), also known as the rigorous coupled wave analysis (RCWA), is employed as a rigorous regional solver for grating simulation. Not just for the calculation of diffraction efficiency, all vectorial electromagnetic effects are included in the FMM/RCWA, and the electromagnetic field interaction with the grating can be visualized. Together with proper parametric optimization methods, gratings for specific applications can be optimized as well.