Independently tunable infrared absorber using stacked molybdenum disulfide metasurfaces

Abstract In this paper, we present an independently tunable infrared tri-band perfect absorber, which consists of double-layer stacked molybdenum disulfide (MoS2) metasurfaces and a gold mirror separated by insulating layers. The light absorption in monolayer MoS2 is strongly enhanced, and three absorption peaks of over 99.5% are achieved. We demonstrate that the three absorption peaks can be independently tuned by changing the carrier density of the corresponding MoS2 layer, indicating no interlayer coupling between the top and bottom MoS2 layers. Based on this, we propose a multilayered multiple interference model to elucidate the independently tunable perfect absorption mechanism. The theoretically calculated absorption spectrum agrees excellently with the simulated spectrum. In addition, the tri-band perfect absorber possesses polarization-independent and incident-angle-insensitive properties. The proposed metasurfaces may help in designing multilayered metasurface absorbers and thus the fabrication of MoS2-based optoelectronic devices such as modulators, tunable sensors, thermal emitters, and photodetectors for infrared waves.