MEASUREMENT OF NONDEGENERATE NONLINEARITIES USING A 2-COLOR Z-SCAN

A simple dual-wavelength (two-color) Z-scan geometry is demonstrated for measuring nonlinearities at frequency omega(p) owing to the presence of light at omega(e). This technique gives the nondegenerate two-photon absorption (2PA) coefficient beta(omega(p); omega(e)) and the nondegenerate nonlinear refractive index n2(omega(p); omega(e)), i.e., cross-phase modulation. We demonstrate this technique on CS2 for n2 and on ZnSe where 2PA and n2 are present simultaneously.