Polarization Discrimination in the Terahertz Range Using Graphene Strip-on-Substrate Grating

Polarization discrimination between the H- and E-polarized plane waves with the aid of the graphene strip grating on dielectric substrate is investigated. Our tool is the numerical analysis using the meshless full-wave techniques based on the semi-inversion and leading to mathematically convergent codes. If the dimensions are on the microsize scale, the studied grating displays the resonances at the THz frequencies. The resonances on the H-polarized plasmon modes are usually attractive thanks to their DC tuning. However, less tunable lattice modes in the either polarization have drastically higher Q-factors. Comparison of the E and H cases reveals two regimes of high polarization selectivity. One of them is the quasi-static Hertz effect due to the high/low reflection of the low-frequency E/H-wave from well-conducting strips. The other is high reflection of the H-wave on the plasmon-mode frequency that can be spoiled if it hits an ultrahigh-Q lattice-mode resonance. This study can be useful for optimized sensor and polarizer designs.