Active tuning of the hybridization effects of mid-infrared surface plasmon resonance in a black phosphorus sheet array and a metal grating slit

Abstract

In this paper, the absorption characteristics of a hybrid structure composed of a black phosphorus (BP) nanostrip array based on localized surface plasmon resonance (LSPR) and a metal grating slit structure have been analyzed systematically. Firstly, we theoretically investigate light-matter interaction in different dimensions of BP nanostrip arrays along armchair and zigzag direction, revealing the absorption property and anisotropic plasmonic response. Besides, the transmission characteristics of the metal grating slit structure with different geometric dimensions are thoroughly analyzed by the transmission spectra and electric intensity distributions. At last, by combining the two structures, we increased the absorption of BP from 72% to 83.6% at 7.04 µm, and this hybrid BP structure demonstrates high absorption at mid-infrared wavelength regime, predicting a promising future for the directional dependent plasmonic devices based on two-dimensional (2D) materials.