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Excitonic nonlinear absorption in CdS nanocrystals studied using Z-scan technique

J. He·W. Ji·G. H. Ma·S. H. Tang·H. I. Elim·W. X. Sun·Z. H. Zhang·W. S. Chin
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Abstract

Irradiance dependence of excitonic nonlinear absorption in Cadmium Sulfide (CdS) nanocrystals has been studied by using Z-scan method with nanosecond laser pulses. The wavelength dependence of nonlinear absorption has also been measured near the excitonic transition of 1S(e)-1S3/2(h). We observe the saturable absorption, which can be described by a third-order and a fifth-order nonlinear process for both 3.0-nm-sized and 2.3-nm-sized CdS nanocrystals. The experimental results show that the excitonic nonlinear absorption of CdS nanocrystals is greatly enhanced with decreasing particle size. A two-level model is utilized to explain both irradiance and wavelength dependence of the excitonic nonlinearity.

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J. He, W. Ji, G. H. Ma, S. H. Tang, H. I. Elim, W. X. Sun, Z. H. Zhang, W. S. Chin. 2005-07-28. Excitonic nonlinear absorption in CdS nanocrystals studied using Z-scan technique. https://doi.org/10.1063/1.1711183

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