Broadband polarization beam splitter based on subwavelength grating in Terahertz

We design a broadband polarization beam splitter (PBS) operating in the terahertz (THz) communication band 0.1THz-1.2THz. The transmittance of the TM mode is larger than 95%, in the meanwhile, the extinction ratio can even reach 49dB. Considering the unavoidable deformation in grating fabrication, we also check the performance of the PBS based on trapeziform grating. Results show that increasing the duty cycle while the slope angle diminishing can effectively increase the TM mode transmittance and the extinction ratio, which can compensate the affection induced by the geometric deformation. This design may achieve some potential applications in THz manipulation system.