Reflection polarizing beam splitter of a fused-silica metal-based sandwiched grating at an incident angle of 45°

We describe a novel reflection polarizing beam splitter (PBS) by a fused-silica metal-based sandwiched grating. The grating period is given with the incident Bragg angle of 45° for simple operation in practice. A special duty cycle of 0.22 is chosen according to the modal method by a two-beam interference of the excited modes in the grating region. And the grating depth and covering layer thickness are numerically optimized using rigorous coupled-wave analysis. The fabrication tolerance around the optimized grating parameters is discussed. Moreover, a more wide tolerance for etched depth is achieved for easy and mass production. The presented PBS of a fused-silica metal-based sandwiched grating can show high efficiency with wideband property for incident wavelength for TE polarization and very high extinction ratio with broad incident angular bandwidth in the –1st order.

► A reflection polarizing beam splitter is proposed by a metal-based grating. ► The wide tolerance for etched depth can be significant for easy and mass production. ► The polarizing beam splitter can show high efficiency and extinction ratio.