1Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean, Nanjing University of Information Science & Technology, Nanjing 210044 2Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044 3School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044
Abstract：To achieve the enhancement and manipulation of light absorption in graphene within the visible and near infrared regions, a design consists of high-contrast gratings and two evanescently coupled slabs with graphene monolayer is demonstrated. The operation principle and design process of the proposed structure are analyzed using the coupled mode theory, which is confirmed by the rigorous coupled wave analysis. It is proved that the absorptance of graphene monolayer can be greatly enhanced to unity. The thickness of grating and slab layers can significantly change the line width and resonant mode position in the absorption spectra. Furthermore, high tunability in amplitude and bandwidth of the absorption spectra can be achieved by controlling the structural parameters of the hybrid structure. The proposed devices could be efficiently exploited as tunable and selective absorbers, and could be allowed to realize other two-dimensional materials-based selective photo-detectors.
2018, Vol. 35 
