Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo, New York 14260-3000, USA.
J Chem Phys. 2009 Dec 7;131(21):214301. doi: 10.1063/1.3266938.
The backward stimulated Bragg scattering (SBgS) of CdTe(x)Se(1-x) quantum dots in chloroform is investigated at three pump laser wavelengths (532, 816, and 1064 nm) in nanosecond regime. The spectral and temporal structures of the backward stimulated scattering and pump threshold dependence on the concentration are presented in this paper. The energy conversion efficiency from input pump pulse to SBgS pulse was measured to be >or=14%. In addition, the samples exhibit multi- (two-, three-)photon absorption capability over the spectral range we investigated. More importantly, both mechanisms of SBgS and multiphoton absorption provided an enhanced optical limiting performance. The measured nonlinear transmissivity was changed from approximately 0.73 to approximately 0.17 for 532 nm laser pulses and from approximately 0.9 to approximately 0.35 for 816 nm laser pulses when the input pulse energy was changed from 10 to approximately 1500 microJ.
在纳秒级条件下，研究了三束泵浦激光波长（532nm、816nm 和 1064nm）下的 CdTe(x)Se(1-x)量子点在氯仿中的反向受激布拉格散射（SBgS）。本文给出了反向受激散射的光谱和时间结构以及泵浦阈值与浓度的关系。测量了从输入泵浦脉冲到 SBgS 脉冲的能量转换效率，其值大于等于 14%。此外，在所研究的光谱范围内，样品表现出多光子（双光子、三光子）吸收能力。更重要的是，SBgS 和多光子吸收这两种机制都提供了增强的光限幅性能。当输入脉冲能量从 10 微焦耳变化到 1500 微焦耳时，对于 532nm 激光脉冲，非线性透射率从大约 0.73 变化到大约 0.17；对于 816nm 激光脉冲，从大约 0.9 变化到大约 0.35。
