The refractive index of graphene depends on wavelength, temperature and chemical potential. Please suggest the formulae from which numerical values can be easily calculated or some code for this.
As the wavelength decreases, in general, the real and imaginary parts of the RI increase. 2 empirical equations that model it are the Cauchy and Sellmeier approaches.
See slide 17 in:
Optical properties of the three forms of titanium dioxide http://tinyurl.com/pbgf9hj