Metal-based phase grating for high-efficiency polarizing beam splitter

We present a novel metal-based phase grating for high-efficiency polarizing beam splitter (PBS), which consists a phase grating etched in fused silica and a metal slab of Ag evaporated on the substrate. The grating parameters are optimized using rigorous coupled-wave analysis. High efficiencies of 97.75% and 96.90% can be achieved for TE and TM polarizations in the - 1st and the 0th orders, respectively. The efficiency is improved greatly for TE polarization compared with the reported transmission binary grating and sandwiched grating. The extinction ratio can reach 1.21×104 with the optimized grating parameters. The proposed PBS grating can have good merits of high efficiency, high extinction ratio, and wide incident wavelength and angular bandwidths for efficiencies higher than 95%. The usual duty cycle of 0.5 and moderate fabrication tolerance would make it easy to be fabricated.