Retrieving linear and nonlinear optical dispersions of matter: combined experiment-numerical ellipsometry in silicon, gold and indium tin oxide

Abstract

We have presented a combined experimental and numerical method that can be used to predict complex nonlinear dispersion curves in almost any material, based exclusively on the experimental determination of harmonic generation conversion efficiencies. We used a hydrodynamic approach that faithfully duplicates linear dispersion, and predicted the wavelength dependent nonlinear response. The method is particularly useful when analytical solutions are not available, as is the case for conductive oxides like ITO, which displays nonlocal effects that trigger an effective anisotropy, and extendable to second order bulk nonlinearities. Our experimental results for THG in silicon suggest that it is possible to exploit its large nonlinear response in the visible and UV ranges, thus opening up new prospects for silicon photonics (Scalora et al., 2019)