▎ 摘　　要

Normal-incidence transmission measurements are commonly used for determining the real part of the in-plane optical conductivities sigma(1)(omega) of graphene layers. We present an accurate expression for sigma(1)(omega) in a closed form for a multilayer graphene film supported on a finite-thickness transparent substrate. This form takes into account the coherent and incoherent multiple reflections of the system, whereas the traditional method assumes a semi-infinite substrate. The simulated results for graphene sheets with a layer number N