▎ 摘　　要

A mechanically exfoliated graphene flake (similar to 150 X 380,mu m(2)) on a silicon, wafer with 98 nm silicon dioxide on top was scanned with a spectroscopic ellipsometer with a focused spot (similar to 100 X 55 mu m(2)) at an angle of 55 degrees. The spectroscopic ellipsometric data were analyzed with an optical model in which the optical constants were parameterized by B-splines. This parameterization is the key for the simultaneous accurate determination of the optical constants in the wavelength range 210-1000 nm and the thickness of graphene, which was found to be 3.4 angstrom. (C) 2010 American Institute of Physics. [doi:10.1063/1.3475393]