Nonlinear absorption and refraction in lead glasses: enhanced by the small metal particle dispersions

We investigate the nonlinear properties of several PbO–B2O3 glasses and their composites using 6-ns laser pulses. The nonlinear index of refraction n2 are measured with Z-scan method at 532 nm for these samples, which are all an order larger than a CS2 solution (n2=0.98×10−11 esu) determined here; the composite materials with silver or copper metal particle dispersions exhibit larger nonlinear refractive index than the related lead glasses. These samples exhibit saturation absorption property at 532 nm under the input irradiance I0 levels from 1.02 to 7.09×10−2 GW/cm2; the estimated saturation absorption coefficient βs(=α0/Is) decreases with increasing I0. The enhancement of nonlinear absorption coefficient β at 355 nm can be attended by either increasing the lead oxide contained in glass matrix or by doping with silver or copper metal particles.