Nonlinear optical response in alkali-silicate glasses at 800 nm femtosecond irradiations

Nonlinear optical response of three alkali-silicate glasses by irradiation of a focused 200 femtosecond pulsed laser were investigated using transmittance measurement at 800 nm. The studied glasses are Na2O-CaO-SiO2, K2O-CaO-SiO2 and Cs2O-CaO-SiO2. The nonlinear transmissions are observed for incident pulse energies of above 35 μJ for Cs2O-CaO-SiO2 sample, 60 μJ for Na2O-CaO-SiO2 sample and 70 μJ for K2O-CaO-SiO2 sample. Femtosecond nonlinear transmittance measurements were used to model the nonlinear behavior of the tested alkali-silicate glasses. The three-photon absorption along with three-photon generated free-carriers within the glasses is main mechanism for the observed nonlinear response. The values of three-photon absorption coefficient and photo-generated free-carrier cross-section are reported for the tested alkali-silicate glasses.