A double-band perfect absorber is proposed based on \(MoS_2\) metamaterial. The proposed absorber is composed of a monolayer molybdenum disulfide, a crystalline silicon layer, and a silver substrate. Utilizing the critical coupling principle of guided resonance, efficient optical absorption of molybdenum disulfide was achieved. Specifically, at the resonance wavelengths ( \(\lambda_{1} = {610}{\text{.431}}\;{\text{nm}}\) , \(\lambda_{2} = {654}{\text{.484}}\;{\text{nm}}\) ), two perfect absorption peaks of 99.42% and 99.31% were attained based on finite-difference time-domain (FDTD) simulations. Through detailed analysis of field distributions and spectral responses, the interactions between electromagnetic waves and this perfect absorber structure are examined. Based on the simulation results, the structure's geometric parameters wield control over the resonance wavelength range of \(MoS_2\) , holding pivotal practical implications for bolstering its absorption potency and selectivity. Moreover, the innovative approach of employing critical coupling to amplify light-silica interactions holds promise for application across various atomic-scale thin materials. Additionally, the absorber's sensing capabilities are revealing many metrics. The highest quality factor, sensitivity, and figure of merit (FOM) of the sensors are recorded as 111.3, 178.4 nm/RIU, and 30.3 \(RIU^{ - 1}\) , respectively. Hence, our findings potentially pave the way for enhancing light-matter interactions within monolayer transition-metal dichalcogenides, offering promise for applications in multiband absorbers and sensors.
