Two-photon absorption in proustite

The two-photon absorption coefficient of proustite was measured at the ruby and neodymium laser wavelengths at pumping intensities up to 35 MW/cm²: Its values were 0.1 and 0.03 cm/MW, respectively. The two-photon absorption exhibited no anisotropy associated with the polarization of the incident radiation. An analysis was made of the limiting influence of the two-photon absorption on the efficiency of parametric conversion.