Linear and nonlinear optical characterization of tellurium based chalcogenide glasses

We investigate the linear and nonlinear coefficient of chalcogenide glasses containing different amount of tellurium (Ge 10 As 10 Se 80− x Te x , where x = 0, 10, 15, 20). We give, for the first time to our knowledge, the values of the linear indices as well as the nonlinear refraction coefficient near the band gap of these materials. We give also, in the transparency region, the Cauchy coefficients for all the compositions (near infrared domain). An estimation of the linear absorption is also made using a ‘cut-back’ method. Nonlinear characterization of these materials is performed using the Z -scan technique at 1064 nm and 15 ps pulsewidth. A good agreement is found when we compare some of the results with those obtained using other techniques (at the same incident intensity). We show that the nonlinear refraction coefficients measured here are among the largest values reported on chalcogenide glasses. Furthermore, we found that the addition of tellurium does not enhance significantly the nonlinear refraction coefficient but exalts more the nonlinear absorption.