Cadmium Chalcogenide Semiconductor Nanocrystals For Optical Power Limiting Application

Cadmium chalcogenide nanocrystals at similar to2-10 nm were synthesized using with a chemical colloidal reaction technique. Strong blue-shifts of the CdTe, CdSe and CdS nanocrystals absorption bandedge and the atomic-like discrete energy states indicate an exciton quantum confinement. Z-scan and I-scan nonlinear spectroscopy revealed that the CdTe nanocrystals quantum dot in toluene (similar to8 x 10(-5) mol/L) has the negative nonlinearity (self-defocusing) with similar to -1 x 10(-1)3 m(2)/W and a high nonlinear figure of merit of similar to200. For the optical power self-limiting experiment, the CdTe nanocrystals was almost opaque above similar to0.8 MW/cm(2) at near valley (zsimilar to6.9 cm) of Z-scan.