Surface plasmon absorption in MoS2 and graphene-MoS2 micro-gratings and the impact of a liquid crystal substrate

Abstract

The absorption coefficients of a far-infrared wave are calculated at normal incidence for MoS2 and graphene-MoS2 micro-ribbon gratings placed between a nematic LC and an isotropic dielectric medium. Maxima in the absorption spectra, which are related to the excitation of the surface plasmons in micro-ribbons of these gratings, are observed. The spectral position of absorption maxima depends on the grating spacing, micro-ribbon width, and conductivity of the ribbons. The impact of the 2D electron concentration of the MoS2 ribbons on the plasmon bands is different for a MoS2-grating versus a graphene-MoS2 grating. The influence of the LC orientational state on the absorption spectra of the gratings enables the manipulation of the absorption peak magnitude.