The effect of surface modification on femtosecond optical Kerr effect of PBS nanoparticles

PbS nanoparticles modified by a polymer (P-PbS) was prepared, and the transient nonlinear optical properties studied by femtosecond optical Kerr effect (OKE) spectroscopy for the first time. A very large nonlinear optical effect ( chi((3)) similar to 5.6 x 10(-12) esu) with response time comparable to the laser pulse (similar to 165 fs) was observed. Comparing with PbS nanoparticles stabilized with PVA and coated with sodium dodecyle benzene sulphonate (DBS), the optical nonlinearity of the PbS nanoparticles modified by the polymer is much larger than those of them. Thereafter, the corresponding nonlinearity mechanism was interpreted. (C) 1999 Elsevier Science B.V. All rights reserved.