Ultrafast, third-order nonlinear optical properties of arsenic-selenium(3) chalcogenide glass

Chalcogenide glasses exhibit an ultrafast nonlinear optical (NLO) response making them excellent candidates for photonic switching devices at communication wavelengths around 1550nm. While the nonlinear Kerr coefficient of As 2Se3 has been studied by several groups, few studies have probed the temporal dynamics of the 3rd order nonlinear response in chalcogenide glasses. For ultrafast time-resolved measurements of Kerr dynamics in chalcogenide glass films, we have developed a wavelength-tunable, time-resolved, differential optical Kerr effect (DOKE) detection system. We have studied the NLO response of As2Se3 films deposited on BK-7 glass substrate by thermal evaporation. We observed a large Kerr response in films as thin as 4.5mum. The obtained Kerr coefficient for As2Se 3, at lambda = 1425nm, was n 2 = 6.7x10-18 m 2/W, and a two-photon absorption coefficient beta = 0.14x10-11m/W. The Kerr response follows the autocorrelation of the pulse and there was no evidence of a slow component in the decay.