Third-Order Nonlinear Optical Response near the Plasmon Resonance Band of Cu2-xSe Nanocrystals  

作　　者：周兰青 张延榜 闫腾飞 李莹 贾国治 许怀哲 张新惠 

机构地区：[1]State Key Laboratory of Software Development Environment and Department of Physics,Beihang University,Beijing 100191 [2]State Key Laboratory of Superlattices and Microstructures,Institute of Semiconductors,Chinese Academy of Science,P.O.Box 912,Beijing 100083 [3]School of Science,Tianjin Chengjian University,Tianjin 300384 [4]College of Materials Science and Opto-electronie Technology,University of Chinese Academy of Sciences,Beijing 100049

出　　处：《Chinese Physics Letters》2017年第1期60-64,共5页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant Nos 11274302,11474276 and 11674240

摘　　要：The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the nonlinear optical response of Cu Se nanocrystals is sensitively dependent on the excitation wavelength and exhibits the enhanced nonlinearity compared with other selenides such as ZnSe and CdSe. The W-shaped Z-scan trace, a mixture of the reversed saturated absorption and saturated absorption, is observed near the plasmon resonance band of Cu Se nanocrystals, which is attributed to the state-filling of free carriers generated by copper vacancies (self-doping effect) of Cu Se nanocrystals as well as the hot carrier thermal effect upon intense femtosecond laser excitation. The large nonlinear optical response and tunable plasmonic band make Cu Se nanocrystals promising materials for applications in ultra-fast all-optical switching devices as well as nonlinear nanosensors.The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the nonlinear optical response of Cu Se nanocrystals is sensitively dependent on the excitation wavelength and exhibits the enhanced nonlinearity compared with other selenides such as ZnSe and CdSe. The W-shaped Z-scan trace, a mixture of the reversed saturated absorption and saturated absorption, is observed near the plasmon resonance band of Cu Se nanocrystals, which is attributed to the state-filling of free carriers generated by copper vacancies (self-doping effect) of Cu Se nanocrystals as well as the hot carrier thermal effect upon intense femtosecond laser excitation. The large nonlinear optical response and tunable plasmonic band make Cu Se nanocrystals promising materials for applications in ultra-fast all-optical switching devices as well as nonlinear nanosensors.

关 键 词：Third-Order Nonlinear Optical Response near the Plasmon Resonance Band of Cu x)Se Nanocrystals 

分 类 号：O53[理学—等离子体物理] TB383.1[理学—物理]