Third-order non-linear optical response in chalcogenide glasses: Measurement and evaluation

In this paper, the temporal dynamics of the non-linear response of chalcogenide glass samples of the system As-S-Se have been studied near the bandgap frequencies of the samples by using the interferometric pump-probe method. The pumping laser frequency was located in the spectral range of the Urbach tail or weak-absorption tail at the edge of the fundamental absorption band (so-called Tauc edge), depending on the glass composition. Peculiarities of the non-linear response of each glass composition depend on the relation of cross-sections of the two- and single- photon absorption at the 790 nm wavelength of the pumping laser.