Polarization beam splitter based on a double-groove slanted grating under normal incidence

In this paper, we propose a one-dimensional polarization beam splitting grating under normal incidence with excellent polarization characteristics and a high diffraction efficiency. The main structure is a double-groove slanted grating. We employed a rigorous coupled-wave analysis and simulated annealing algorithm for numerical calculations of the grating. The optimized grating structure can concentrate the energy of TE-polarized light at the -1st order and the energy of TM-polarized light at the 0th order under normal incidence. The analysis results indicate that at the incident wavelength of 1550 nm, the diffraction efficiency is 93.549% for TE polarization and 93.522% for TM polarization, with an extinction ratio greater than 14 dB. To the best of our knowledge, this is the first report of a one-dimensional polarization beam splitter grating with a transmissive double-groove slanted grating under normal incidence. This grating shows great potential for applications in polarization measurement, imaging, and grating encoders. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.