Nonresonant Optical Nonlinearities of Surface Chemically Modified ZnO Composite Nanoparticles

With surface chemical modification,we have obtained core-shell structure ZnO nanoparticles.The nonresonant third-order nonlinear optical refraction of this new composite material was found to be-3.8×10^(-10) esu by Z-scan measurements with a femtosecond pulsed laser.The ultrafast nonlinear response time~250 fs measured by time-resolved pump-probe techniques suggests that the nonlinearity of this new material originates mainly from a rapid electronic polarization process or virtual process such as the optical Stark effect.