A new ellipsometric approach for determining dielectric function of graphene in the infrared spectral region

Simple ellipsometric method for determining dielectric constants of absorbing two-dimensional materials on dielectric substrates is developed. The method is based on the analytical formulas obtained in the framework of a long-wave limit. An important feature of this approach lies in the fact that for data handling the problematic numerical calculation methods are not in use. The inversion problem is resolved analytically. The developed method has no need for the initial guesses of the desired parameters that is very useful from the practical point of view, for example, in the light of in-line control.