文献类型：期刊文献

英文题名：Ultrafast Saturable Absorption of Core/Shell Colloidal Quantum Dots

作者：Li, Jingzhou[1,2];Zhang, Saifeng[1];Dong, Hongxing[1];Ma, Yunfei[3];Xu, Bin[4];Wang, Jun[1];Cai, Zhiping[4];Chen, Zhanghai[5,6];Zhang, Long[1,7]

机构：[1]Chinese Acad Sci, Shanghai Inst Opt & Fine Mech, Key Lab Mat High Power Laser, Shanghai 201800, Peoples R China;[2]Univ Chinese Acad Sci, Beijing 100049, Peoples R China;[3]East China Univ Sci & Technol, Adv Mat Lab, Dept Chem, Shanghai 200237, Peoples R China;[4]Xiamen Univ, Dept Elect Engn, Xiamen 361005, Peoples R China;[5]Fudan Univ, State Key Lab Surface Phys, Shanghai 200083, Peoples R China;[6]Fudan Univ, Dept Phys, Shanghai 200083, Peoples R China;[7]Shanghai Jiao Tong Univ, IFSA Collaborat Innovat Ctr, Shanghai 200240, Peoples R China

年份：2017

卷号：34

期号：1

外文期刊名：PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION

收录：;EI(收录号：20164302939413);WOS:【SCI-EXPANDED(收录号:WOS:000393580600005)】；

基金：This work was supported financially by the NSFC (61378074, 61475173, 61308034, 61575164). Sponsored by Shanghai Rising-Star Program (A type 14QA1404000), and the Youth Innovation Promotion Association of Chinese Academy of Sciences. The authors acknowledge Prof. Donghai Feng and Dr. Ningning Dong for his kind help with pump-probe spectroscopy and open-aperture Z-scan experiments, respectively. The authors also thank Prof. Xinhua Zhong for the help with the synthesis of the nanocrystals.

语种：英文

外文关键词：colloidal quantum dots; nanophotonics; nonlinear optics; Q-switched; quantum confinement effects; saturable absorption

摘要：Ultrafast saturable absorption (SA) materials that are capable of blocking the optical absorption under strong excitation have extensive applications in photonic devices. This work presents core/shell colloidal quantum dots (CQDs) which have the quantized energy levels, excellent band gap tunability, and possess significant SA performance. When the band gap is close to the pump pulse energy, the CQDs show significant resonant SA response. At the same excitation conditions, the core/shell CQDs dispersions show better SA response than graphene dispersions, and comparable to the recently reported molybdenum disulfide. The carrier dynamics of the SA of the CQDs is analyzed systematically. The research has also found that the two-photon absorption of the CQDs show nearly cubic power law of the band gap, while the SA performance keeps almost the same in the nonresonant regime. Further, superior passive Q-switched laser behavior is observed using the CQDs as a saturable absorber. The results directly reveal the physical processes of this basic problem and broaden the applications of CQDs in photonic devices.