▎ 摘　　要

Structural and defective information in graphene are usually detected by Raman spectroscopy and electrical techniques; however, less attention has been paid to the spectroscopic ellipsometry investigation on graphene. Here, optical responses of graphene grown by chemical vapor deposition (G), reduced graphene oxide (RGO). restored RGO. and etched RGO are characterized by spectroscopic ellipsometry. The Lorentz oscillator model is used to fit the ellipsometric parameters. The resulting optical constants, refractive index and extinction coefficient are higher in less defective graphene, i.e. G and restored RGO. The results can be correlated with the Raman spectroscopic observation - fewer defects leading to higher density and more optical absorption. Our investigation opens a new angle of view to probe the structural information in the defective graphene and thus favors the production of high-quality graphene. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement