Optical Nonlinear Properties of CdSeS/ZnS Core/Shell Quantum Dots

The optical nonlinear properties of CdSeS/ZnS quantum dots (QDs) are investigated by Z-scan technique using fundamental harmonic generation (1064 nm) of mode-locked Nd:YAG laser for the first time. The experimental results show that two photon absorptions (TPA) occur at input intensity up to 12.5 GW/cm2. CdSeS/ZnS QDs have an average TPA cross section of 13710 GM and large nonlinear refractive index on order of 10-7 esu. The large optical nonlinearities perhaps allow the CdSeS/ZnS QDs to be one kind of candidate material for bioimaging and fluorescence label, optical limiting and all-optical switching.