Tunable absorption characteristics in multilayered structures with graphene for biosensing

Abstract

Graphene derivatives, possessing strong Raman scattering and near-infrared absorption intrinsically, have boosted many exciting biosensing applications. The tunability of the absorption characteristics, however, remains largely unexplored to date. Here, we proposed a multilayer configuration constructed by a graphene monolayer sandwiched between a buffer layer and one-dimensional photonic crystal (1DPC) to achieve tunable graphene absorption under total internal reflection (TIR). It is interesting that the unique optical properties of the buffer-graphene-1DPC multilayer structure, the electromagnetically induced transparency (EIT)-like and Fano-like absorptions, can be achieved with pre-determined resonance wavelengths, and furtherly be tuned by adjusting either the structure parameters or the incident angle of light. Theoretical analyses demonstrate that such EIT- and Fano-like absorptions are due to the interference of light in the multilayer structure and the complete transmission produced by the evanescent wave resonance in the configuration. The enhanced absorptions and the huge electrical field enhancement effect exhibit potentials for broad applications, such as photoacoustic imaging and Raman imaging.