SbS3 enhanced ultrafast third-order optical nonlinearities of Ge–S chalcogenide glasses at 820nm

Abstract GeS2 based multi-component chalcogenide glasses, Ge–S–Sb(Cd), were prepared in series. With femtosecond time-resolved optical Kerr gate technique, we investigate their ultrafast third-order nonlinear optical (NLO) properties. The strongest NLO response comes from 0.70GeS2–0.30Sb2S3. Its χ(3), 1.8 × 10−12 esu, is more than three times to GeS2 glass. Their instant NLO responses are within 120 fs pulse duration. We suggest that lone-pair electrons from highly polarizable Sb atom in [SbS3] structure unit play an important role for the enhanced NLO response. This enhancement is much stronger to the contribution from S–S covalent bond.