A study on the optimal incident angle of sub-wavelength grating polarization beam splitter

One problem faced by the sub-wavelength grating polarization beam splitter is the lack of a generally-used formula able to conduct accurate calculation of the incident angle. With that background, by the design method of optical film polarization beam splitter, this work realizes an precise calculation under the condition of arbitrary grating constants by transforming the splitter into an optical-film-structure model. According to tests, the incident angles of grating calculated by the method proposed here are consistent with those obtained from the FDTD simulation, illustrating the reliability of applying the polarization beam splitting design method of optical thin films to polarization beam splitting gratings.