Nonlinear refraction and nonlinear absorption of CdSe_0.3S_0.7/ZnS quantum dots

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• 作者：Feng Wu ; ^{ourdaywufeng2000@gmail.com} ; Aihua Liu ; Hong Zheng ; Haitao Chang ; Peng Shi ; Kaixuan Cheng ; Xiaoman Cheng
• 刊名：Physica E
• 出版年：2012
• 期刊代码：139_13869477
• 类别：et
• 出版时间：April-May, 2012
• 卷：44
• 期：7-8
• 页码：1158-1161
• 文件大小：438 K

摘要

Nonlinear optical properties of CdSe_0.3S_0.7/ZnS quantum dots(QDs) were investigated by Z-scan technique using the Nd:YAG laser second harmonic radiation (位=532 nm, t=35 ps). The Z-scan results show that the CdSe_0.3S_0.7 QDs have strong reverse saturable absorption(RSA). Based on the linear absorption spectrum and one-photon resonant fluorescence spectrum, it is reasonable for us to infer that the nonlinear absorption arises from free carrier absorption(FCA). Based on standard Z-scan theory, we obtain the FCA cross section and nonlinear refractive index of CdSe_0.3S_0.7/ZnS QDs. These QDs have average absorption cross section of 2.8脳10^鈭?6 cm² and nonlinear refractive index on order of 10^鈭? esu. The strong nonlinear absorption and large nonlinear refractive index perhaps allow them to be applicable in the optoelectronic field.