Investigation of dual-band perfect absorption and their hybridization on multilayer tungsten disulfide (WS2) gratings

We investigate the dual-band perfect absorption and their hybridization on multilayer tungsten disulfide (WS2) gratings with metallic substrates by the finite-difference time-domain method and the coupled-mode theory. Numerical results suggest that, under the illumination of the transverse magnetic polarized plane wave, the special multilayer WS2 grating with high refractive index not only allows the circulating-current-drove magnetic resonance but also provides additional wavevectors to excite the plasmonic resonance on the substrate surface simultaneously. Consequently, the dual-band perfect absorption is obtained in the single-port system by two independent critical coupling. The effect of small changes in the grating period, width, and height on spectral positions of absorption peaks is presented. The inherent multiple dielectric resonances on the WS2 grating under the illumination of the transverse electric polarized plane wave are also demonstrated. Intriguingly, the simultaneous existence of angle-independent magnetic resonances and angle-dependent plasmonic resonances gives rise to the obvious hybridization between the two types of resonances under the oblique incidence. Numerical results are in excellent agreement with theoretical calculations. The structure under study undoubtedly opens perspectives for enhancing light-matter interactions in two-dimensional materials. Published under an exclusive license by AIP Publishing.

Automated summary

This study investigates dual-band perfect absorption and hybridization on multilayer WS2 gratings with metallic substrates using the finite-difference time-domain method and coupled-mode theory. The results show that achieving dual-band perfect absorption in a single-port system relies on two independent critical couplings.