Resonant perfect absorption of molybdenum disulfide beyond the bandgap

Abstract

Light absorption and radiation process is one of the 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 coexisted since its extremely weak light-matter interaction capability beyond its energy band. In this work, we designed a kind of sandwich resonance structure and expressed MoS2 first as a perfect absorber in infrared spectrum that should be transparent according to optical band theory. The infrared absorption properties of W or Au/MoS2/Au models in 800–2400 nm were systematic simulated. By optimizing the structural parameters, the resonant wavelength of perfect absorption can be modulated from 830 to 1700 nm with angle-insensitivity and polar-independence. Moreover, we discovered the bandwidth of absorption exceeding 50% of W-top model reaches 500 nm, while that of Au-top model is less than 100 nm, indicating the top metal material used have a great influence on the resonance absorption spectrum. Our works provide a practical route to enhance and manipulate 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.