LAUSR

The nonlinear optical properties of InP/ZnS core-shell quantum dots toluene solution were investigated by Z-scan and transient absorption technique with femtosecond pulses and nanosecond pulses at 532 nm wavelength respectively. The research results showed that InP/ZnS core-shell quantum dots exhibited saturated absorption under the excitation of femtosecond pulses, and the switch from saturation absorption to reverse saturation absorption was observed under the excitation of nanosecond pulses. The mechanism of the switch was attributed to excited-state absorption. Besides, the nonlinear refraction was shown as self-focusing and self-defocusing under the excitation of femtosecond and nanosecond pulses respectively which were attributed to the Kerr effect of electrons and the thermal effect of InP/ZnS quantum dots respectively. The investigations showed that InP/ZnS core-shell quantum dots were good materials and had many potential applications in optical and electrical fields.