Experimental observation of higher order nonlinear absorption in tellurium based chalcogenide glasses

International audienceWe show that highly nonlinear two-photon absorption coefficients can be obtained in infrared glasses (tellurium based chalcogenide glasses) at 1.06 lm and in the picosecond range (twice that of As2 Se3 ). We observe an intensity-dependant two-photon absorption coefficient. This dependence is attributed to higher order effects occurring in non-linear absorption process in our materials. The corresponding nonlinear coefficients are deduced from experimental data using a closed-form relation relating the effective two-photon absorption coefficient to the incident intensity. These coefficients become larger as the photon energy increases relative to the band gap