Pan Han, Chu Hongwei, Li Ying, Qi Na, Zhao Shengzhi, Li Guiqiu, Li Dechun
School of Information Science and Engineering, Shandong University, Qingdao 266237, People's Republic of China.
Nanotechnology. 2020 May 8;31(19):195703. doi: 10.1088/1361-6528/ab7045. Epub 2020 Feb 21.
The colloidal CdSe/ZnS quantum dots (QDs) in the PMMA polymer film with different QDs concentrations were fabricated. The influence of QDs concentration and excitation pump energy on nonlinear optical (NLO) properties of PMMA capped CdSe/ZnS QDs was investigated by the Z-scan technique with nanosecond laser pulses in the near-infrared spectral band. A large effective nonlinear absorption coefficient (β ∼ -10 esu) due to the saturable absorption was observed. It was found that the appropriate concentration could lead to the reinforcement of NLO effect. In addition, the impact of the excitation energy on the nonlinear refractive index n , real and imaginary parts of the third-order nonlinear optical susceptibility was also performed. This study involving the light-matter interactions in the colloidal quantum dots will benefit potential NLO-based applications of optoelectronics, optical modulation and photonics.
制备了不同量子点浓度的聚甲基丙烯酸甲酯（PMMA）聚合物薄膜中的胶体CdSe/ZnS量子点（QDs）。采用Z扫描技术，利用近红外光谱波段的纳秒激光脉冲，研究了量子点浓度和激发泵浦能量对PMMA包覆的CdSe/ZnS量子点非线性光学（NLO）性质的影响。观察到由于饱和吸收导致的大有效非线性吸收系数（β ∼ -10 esu）。发现适当的浓度可以导致NLO效应的增强。此外，还研究了激发能量对非线性折射率n、三阶非线性光学极化率实部和虚部的影响。这项涉及胶体量子点中光与物质相互作用的研究将有利于基于NLO的光电子学、光调制和光子学的潜在应用。
