  Using an Electrically Focus Tunable Lens (EFTL), an integrating sphere and a
tunable femtosecond-pulse laser (Mai Tai HP), we were able to measure the
degenerate two-photon absorption coefficient (in transmission) of CdS and ZnSe
in a long range of wavelengths (690-1040 nm), with a 5 nm resolution, in less
than 30 minutes. We compared our results with theoretical approaches for the
dispersion relations of the non-linear properties of semiconductors, and found
excellent agreement with the experimental results. The system has no moving
parts, is highly compact, and is fully automated.
