Broadband Z-scan characterization using a high spectral irradiance high quality supercontinuum

Abstract

We generate a high-spectral-irradiance, high-quality continuum by weakly focusing femtosecond pulses in Kr gas. We use this continuum as a source for rapid Z-scan measurements of the degenerate nonlinear absorption spectrum and the associated dispersion of the nonlinear refraction in optical materials throughout the visible. We measure the degenerate two-photon absorption spectra and the dispersion of the nonlinear refractive index, n 2 , of two well-characterized semiconductors (ZnSe and ZnS ) as reference samples for our method, along with dilute solutions of organic materials. The latter materials demonstrate application of the technique to samples with lower nonlinearities.