Approach for eliminating the zeroth order by T-type grating with polarization loss reduction

We describe a two-port reflective beam splitter with the elimination of the zeroth order based on T-type metal grating. Under the condition of a normal incidence wavelength lambda = 1.550 mu m, for transverse electric (TE) polarization, the grating efficiencies of the zeroth and +/- first orders can reach 1.35% and 48.28%, respectively. And for transverse magnetic (TM) polarization, efficiencies reach 0.49% and 48.30%, respectively, where energies of the zeroth order are suppressed well for both TE and TM polarizations. Furthermore, the numerical analysis indicates that the grating has a wide incident bandwidth (the efficiencies of over 47% at a bandwidth of 118 nm) as well as an excellent process tolerance in period and duty cycle. The grating performance is also stable with a simple structure so that it has a wide application prospect in optical polarization devices, laser systems, polarization imaging, etc. (c) 2022 Society of Photo-Optical Instrumentation Engineers (SPIE)