Independent tunable multi-band absorbers based on molybdenum disulfide metasurfaces

In this paper, we theoretically and numerically demonstrate a dual-band independently adjustable absorber comprising an array of stacked molybdenum disulfide (MoS₂) coaxial nanodisks and a gold reflector that are separated by two dielectric insulating layers. The array plane functionality is explained by the dipole resonances with the MoS₂ nanodisks. As a result, strong absorption is achieved at a wide range of incident angles under TE and TM polarizations. The structural parameters of the entire array and the carrier concentration in the MoS₂ layers were varied to get the optimized absorption. The absorptance positioning can be adjusted by scaling the diameters of the MoS₂ disks. We also proposed the array modification where nanodisks are replaced by a layer with nanoholes. The position of both absorptance peaks can be adjusted individually by changing the carrier concentration in the array. This structure can be useful for the design of chemical sensors, detectors or multi-band absorbers.