Ultrafast nonlinearity of antimony polyphosphate glasses

We report on the ultrafast nonlinearity of antimony polyphosphate glasses measured using the Kerr shutter technique. The nonlinear refractive index, n2, was (1.1±0.2)×10−14 cm2/W at 800 nm, and enhancement of n2 by ≈80% was observed by adding 10% of lead oxide in the glass composition. The full width at half-maximum of the third-order correlation signal was 150 fs, which implies a fast response of the samples (⩽100 fs). Nonlinear absorption was negligible in the range of intensities used.