Simulation of the optical properties of gold nanoparticles on sodium alginate

. In this contribution, we report on the simulation of optical reflectance and transmittance (R&T)taken on a set of gold nanoparticles thin film, deposited on sodium alginate by magnetron sputtering. Thegold layer is very thin, so that the films are not continuous and the material is arranged in nanostructuredlayers.R&T spectra are simulated using the Generalized Transfer Matrix method applied to the film-on-substratemodel. The gold NP films are simulated using the Drude-Lorentz model, by taking into account that theoptical function of nanostructured gold exhibits increased collision frequency and reduced relaxation time.Moreover, the signal of localized surface plasmon, evident in the spectra, is simulated by introducing adedicated modified Lorentz oscillator.The experimental results are well reproduced by the applied model. All trends (amplitude and energyposition of the plasmon oscillator, film thickness, relaxation time) are correlated with the depositionparameters. The procedure represents a useful tool in the characterisation of such nanoparticles thin films