Nanoparticles of arbitrary form in the Maxwell-Garnett theory

The technique of improvement of the Maxwell-Garnett theory of electric permittivity averaging for precise evaluation of composite material dispersion is demonstrated. According to this approach, a set of adjustable coefficients in depolarization factor are introduced, which are determined in the process of fitting simulated optical spectra to experimentally measured ones. The presentation gives the results of depolarization coefficient calculation from reflection and transmission spectra of simulated in finite difference time domain method test structures and from experimentally measured spectra of samples with non-uniform nanoparticles distribution. The proposed approach shows good convergence with the experimental data and could be used as a versatile dispersion model in optical metrology of composite materials with unknown arbitrary concentration and shapes of inclusions.