FEMTOSECOND MEASUREMENT OF ENHANCED OPTICAL NONLINEARITIES OF SULFIDE GLASSES AND HEAVY-METAL-DOPED OXIDE GLASSES

Studies of the nonlinear absorption and refraction of a variety of heavy-metal oxide and sulfide glasses are reported. The third-order nonlinearities were measured with similar to 100-fs pulses at wavelengths between 600 nm and 1.25 mu m, allowing for what we believe is the first systematic study of the dispersion of the third-order nonlinearities of these glasses. The results confirm that the nonlinearities of heavy-metal oxide glasses are determined by heavy-metal content, as reported previously. The measured nonlinear refractive indices are predicted reasonably well by the semiempirical Boling-Glass-Owyoung formula and include several results that are among the largest nonresonant nonlinearities reported. The measured dispersion of the nonlinearities is consistent with simple theoretical expectations. Finally, most of the glasses obey Kleinman's symmetry, from which we conclude that the origin of the femtosecond-time-scale nonlinearities is electronic. (C) 1995 Optical Society of America