▎ 摘　　要

We investigated the optical contrast of graphene in the various stacked structures which composed of a variety of materials using Fresnel's equation and the transfer matrix method. The optical imaging method is widely known as the simplest method to determine the number of layers in two-dimensional (2D) materials with layered structure. We expanded the method to the simple two-layer structure with transparent substrate and graphene and a rather complex structure including polymers, different from the typical graphene/SiO2/Si structure. Furthermore, we propose a new technique for identifying the thickness of polymer films using the contrast spectrum of graphene quickly and cost-effectively without additional equipment. It is expected to allow precise control in the condition of device fabrication owing to good estimation of the thickness of a polymer around graphene. In this paper, we demonstrated that optical imaging techniques can be applied to devices with various stacked structures to confirm the number of layers of 2D materials and to measure the thicknesses of polymers nondestructively.