Exploiting black phosphorus based-Tamm plasmons in the terahertz region

Polarization-sensitive Tamm plasmons are investigated in a multi-layer photonic configuration where a monolayer black phosphorus (BP) is coated on a Bragg mirror separated by a dielectric. Owing to the in-plane anisotropy of BP, the Tamm plasmon can be excited selectively by tuning the BP carrier density. Cross-polarization conversion occurs when the armchair direction of BP makes an angle with the incident plan, i.e., phi not equal 0 or 90 degrees. The BP-based Tamm device can be used as an intensity modulator with a modulation depth up to similar to 100% and an insertion loss smaller than -0.55 dB. By analyzing the polarization evolution carefully, a multichannel polarization division multiplexing scheme is proposed and discussed. These findings open a new avenue for exploiting versatile tunable THz devices based on the monolayer of BP. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement