Optimization design of polarizing beam splitter based on metal-multilayer dielectric reflecting grating

In this paper, a reflecting polarizing beam splitter (RPBS) with a metal-multilayer dielectric grating (MMDG) structure is designed by using a genetic algorithm and the Fourier mode method. The proposed RPBS grating can be operated at a central wavelength of 1053 nm. Moreover, this grating can reflect the transverse electric wave in the -1st order and the transverse magnetic wave in the 0th order. The optimized RPBS grating has high extinction ratios of over 20 dB from 1030 nm to 1076 nm at angles ranging from 48.6° to 55.1°. At 1053 nm, the highest efficiency of over 98%, as well as polarization extinction ratios of the 0th order and -1st order at 62.2 dB and 48.8 dB, respectively, is obtained. The optimized MMDG structure shows acceptable tolerances for grating fabrication. This MMDG may be a potential RPBS candidate for use in different optical systems.