Nonlinear optical response and optical properties modification in crown B270 glass sample with fs laser pulses

In this paper, the nonlinear optical responses and the optical properties modification in crown B270 glass are studied under irradiations of the CPA Ti: Sapphire laser (?=200 fs,?=800 nm and R=1 kHz). The single beam z-scan method and هInput-output measurement are applied to study the nonlinearity. The nonlinear refraction and absorption coefficient of the sample are evaluated at three different 4, 5 and 6 ? 102 GW/cm2 incident intensities. The pairs of {n2 (?10-7 cm2/GW), ? (?10-3 cm/GW)} are measured to be {2.06, 4.33}, {2.33, 5.82} and {2.59, 7.21}, respectively. The intensity dependency of the nonlinear refraction and absorption coefficient indicates that the higher order nonlinear responses are also encountered. The Optical power limiting threshold of the sample is measured to be about 30 µJ. An erasable modification, called color centers, is observed in the sample after irradiation with 800 nm (IR) femtosecond laser pulses.