▎ 摘　　要

Spectroscopic ellipsometry was used to characterize the optical response of few layer reduced graphene oxide and graphene oxide in visible range. Lorentz oscillator model is added to analyze the ellipsometric parameters. The experiment shows the optical response of few layer reduced graphene oxide and monolayer exfoliated graphene in visible range is quite similar with slight difference due to the structure defects. The Lorentz oscillator model gives experimental support to investigate the band-gap tuning through the reduction process in details. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3646908]