THIRD-ORDER NONLINEAR OPTICAL PROPERTIES OF SnO2 NANOPARTICLES

We have measured the third-order nonlinear susceptibilities $\chi$⁽³⁾ of SnO₂ nanoparticles both naked and coated with a layer of stearic acid by using Z-scan technique with 1.06μm pulse from a Q-switched Nd:YAG laser. The results show that the $\chi$⁽³⁾ of these nanoparticles is much larger than that of the bulk material. Moreover, we find that two-photon absorption is not present for the naked nanoparticles but it is preseut for the coated ones, and the $\chi$⁽³⁾ of the latter is larger than that of the former. It is demonstrated that the surface situations of the nanoparticles have great influence on their nonlinear optical properties.