Tunable plasmon-induced transparency based on monolayer black phosphorus by bright-dark mode coupling

Abstract

We theoretically propose a compound metasurface structure consisting of a patterned black phosphorus (BP) sheet sandwiched by dielectrics, which can achieve a tunable plasmon-induced transparency (PIT) effect in the mid-infrared region. The PIT effect can be actively adjusted by changing the geometric parameters and the carrier concentration of BP. The mechanism of PIT originates from the near-field coupling between the bright mode and the dark mode. The numerical simulation results are highly consistent with the theoretical calculations of the coupled Lorentz oscillator model. In addition, our proposed structure system exhibits a strong dispersion accompanied with a group index of ∼15, which provides a new strategy for slow light devices.