Design and modeling of photonic crystal Absorber by using Gold and graphene films

A novel absorber based on a one-dimensional photonic crystal (PhC) is proposed by combining the absorption property of gold and graphene films. We designed two photonic crystals consisting of silicon and silicon dioxide layers with lattice constants 125 and 260 that alternate in one dimension. We placed a 125-nanometer-thick layer of graphene between the two photonic crystals and an 8-nanometer-thick layer of gold at the end of the second photonic crystal. When graphene is placed between two photonic crystals, a topological edge mode excitation creates a strong absorption enhancement. In this study, the absorbing spectrums and field distribution are analyzed by using the transfer matrix and the 2.5 dimensional variational finite difference time domain method (2.5 var.FDTD). The absorption spectrum for different angles was studied (θ=0 to 60), and more than 87 percent absorption can be maintained for θ =40°. The results of our studies will enhance the interaction between light and matter. Thus, opening up the possibility of their application for the absorption and modulation of light. Keywords: Photonic crystals, Absorber, Gold nanostructures,Graphene.