Ultrafast and Large Third-Order Nonlinear Optical Properties of CdS Nanocrystals in Polymeric Film

We report the ultrafast and large third-order nonlinear optical properties of CdS nanocrystals (NCs) embedded in a polymeric film. The CdS NCs of 2 nm radius are synthesized by an ion-exchange method and highly concentrated in the two layers near the surfaces of the polymeric film. The two-photon ab...

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Bibliographic Details
Published in:The journal of physical chemistry. B 2005-03, Vol.109 (10), p.4373-4376
Main Authors: He, J, Ji, W, Ma, G. H, Tang, S. H, Kong, E. S. W, Chow, S. Y, Zhang, X. H, Hua, Z. L, Shi, J. L
Format: Article
Language:English
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Summary:We report the ultrafast and large third-order nonlinear optical properties of CdS nanocrystals (NCs) embedded in a polymeric film. The CdS NCs of 2 nm radius are synthesized by an ion-exchange method and highly concentrated in the two layers near the surfaces of the polymeric film. The two-photon absorption coefficient and the optical Kerr coefficient are measured with laser pulses of 250 fs duration at 800 nm wavelength. The one-photon and two-photon figures of merit are determined to be 3.1 and 1.3, respectively, at irradiance of 2 GW/cm2. The observed nonlinearities have a recovery time of ∼1 ps. The two-photon-generated free carrier effects have also been observed and discussed. These results demonstrate that CdS NCs embedded in polymeric film are a promising candidate for optical switching applications.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp047787q