Research on the Impact of Geometry on the Absorber Using Finite Difference Time Domain and Simulation Analysis

Absorbers made of traditional materials are mainly aimed at strong absorption. Usually, they have shortcomings such as large structure size, fixed absorption frequency, low absorption rate per unit thickness, and untunable operating frequency. Through artificially engineered microstructures, metamaterials can acquire exotic but very useful dynamic material properties, thereby enhancing the absorption efficiency of absorbers. This paper investigates the effect of material and geometry on the absorption characteristics of the absorber. The overall shape of the absorber is a laminated structure composed of gold as the substrate, silicon dioxide and silicon alternately superimposed, and the upper and lower surfaces of the top silicon are covered with graphene to achieve broadband absorption in the visible light band. Using Finite Difference Time Domain(FDTD) to carry out simulation analysis, the results show that under the same structure, under the dual influence of geometric shape and material properties, adding graphene coating to the square structure can improve the absorption rate of the model, but circular structure is not sensitive to the number of graphene layers, Under the same material, the square structure model has better absorption characteristics than the circular structure model.