Resonant perfect absorption of molybdenum disulfide beyond the bandgap

Abstract

Light absorption and radiation are fundamental processes in optical science and engineering. Materials with perfect absorption properties play an important role in numerous optical applications. Following the meteoric rise of MoS2 material, global opportunities and challenges coexist due to its extremely weak light–matter interaction capability beyond its energy band. In this work, we designed a kind of sandwich resonance structure and investigated MoS2 as a perfect absorber in the infrared spectrum that should be transparent according to the optical band theory. The infrared absorption properties of W or Au/MoS2/Au models at 800 nm–2400 nm were systematic simulated. By optimizing the structural parameters, the resonant wavelength of perfect absorption can be modulated from 830 nm to 1700 nm with angle insensitivity and polar independence. Moreover, we discovered that the bandwidth of absorption exceeding 50% of the W-top model reaches 500 nm, while that of the Au-top model is less than 100 nm, indicating that the top metal material has a great influence on the resonance absorption spectrum. Our work provides a practical route for enhancing and manipulating the light–matter interactions of low-dimensional materials beyond their own band gaps, which will be critical in the future design and implementation of optoelectronic devices and systems.