Balu Mihaela, Hales Joel, Hagan David, Van Stryland Eric
Opt Express. 2005 May 16;13(10):3594-9. doi: 10.1364/opex.13.003594.
We use a white-light continuum (WLC) Z-scan technique to measure the degenerate two-photon absorption spectrum and associated dispersion of the nonlinear refraction in ZnSe. The spectral components of the WLC source are separated by using a narrow band variable filter to minimize nondegenerate nonlinearities. We observe a change in sign of the ultrafast nonlinear refractive index around 0.7 of the bandgap energy as predicted by theory.
