【作者】 张诗按；

【导师】 孙真荣；

【作者基本信息】 华东师范大学 ， 光学， 2006， 博士

【摘要】 基于超快脉冲整形相干控制技术是这是国际上近年来兴起的前沿研究领域之一，它在相干控制化学反应、强激光控制电离、高次谐波和阿秒脉冲的产生及相干控制量子态转移并进而实现量子信息的处理和存储等方面具有非常重要的应用价值。本文基于自适应脉冲整形技术重点研究了双光子跃迁、二次谐波产生以及受激拉曼散射的相干控制，其主要内容包括： (1) 回顾了傅立叶变换飞秒激光脉冲整形的物理基础、脉冲整形系统、脉冲整形测量技术(SHG-FROG技术和SPIDER技术)。研究了基于空间光学调制器(SLM)的脉冲整形的相干控制技术以及相关的基因遗传算法。 (2) 通过方波调制光谱相位分布的深度、周期以及初始相位实现了香斗素515中双光子荧光相干控制，通过优化反馈控制的方法实现了双光子荧光的增强。SHG-FROG研究表明双光子荧光增强归于正啁啾脉冲，在此基础上给出了增强机制的简单模型，并进行了相关的实验验证。 (3) 基于基因遗传算法脉冲整形优化反馈控制的方法研究了BBO晶体二次谐波产生，优化后晶体二次谐波产生增强了约16％。SPIDER结果显示了相对于略有正啁啾原始激光脉冲而言，优化后激光脉冲略有负啁啾且脉宽更短。通过周期性方波调制光谱相位，BBO晶体的二次谐波产生可以有效地被控制。这些实验结果显示了超短激光脉冲产生的二次谐波主要是通过宽带激光光谱中同频率的和频(就是所谓的倍频)以及不同频率之间的和频来产生，前者取决于激光脉冲的峰值功率，后者不仅取决于脉冲的峰值功率而且取决于光谱的相位。 (4) 通过方波调制光谱相位分布的深度、周期以及初始相位在二溴甲烷溶液实现相干拉曼散射信的相干控制，通过优化反馈控制方法实现了相干反斯托克斯拉曼的增强，信号强度增强了大约7.6倍。SHG-FROG研究表明脉宽压缩和反直觉泵浦和斯托克斯脉冲序列有利于STIRAP相干布居转移，从而增强相干拉曼的效率。 (5) 通过脉冲整形优化反馈控制的方法成功实现了苯溶液的相干反斯托更多还原

【Abstract】 Coherent control based on femtosecond pulse shaping is one of the hot and developing fields, and it has been widely applied on controlling chemical reaction, high intense laser ionization, high harmonic generation, attosecond pulse generation, coherent control transfer, and future on the process and storage of quantum information. In this thesis, we focus on investigating the coherent control of two-photon transitions, second harmonic generation and stimulated Raman scattering based on adaptive pulse shaping technique.(1) The basic theory for Fourier transformed pulse shaping technique and development of the pulse shaping and measurement technique are systematically reviewed, and femtosecond adaptive pulse shaping based on spatial light modulator (SLM) and genetic algorithm are successfully achieved.(2) The two-photon transition probability in Coumarin 515 can be effectively controlled by modulating the spectral phase with periodic square distribution (including of the modulation depth, period and phase), and the two-photon fluorescence signal can be efficiently enhanced by adaptive feedback control, and second harmonic generation frequency-resolved optical gating (SHG-FROG) traces indicate that the optimized laser pulses are positive chirp, which are in favor of the effective population transfer in two-photon transitions. A simple theoretical model is used to illustrate effective population transfer in two-photon transitions, which can be experimentally validated.(3) An optimal feedback control of second harmonic generation (SHG) in BBO crystal excited by shaping femtosecond laser pulses based on genetic algorithm is demonstrated experimentally, and SHG in BBO crystal can be enhanced by -16%. SPIDER results show that the optimal laser pulses have shorter pulse-width with the little negative chirp than the original pulse with the little positive chirp. By modulating the spectral phase with periodic square distribution on SLM, the SHG can be effectively controlled, and the experimental results indicate that the SHG with ultra-short pulse is related to sum frequency generation both between the same frequencies (harmonic generation) and different frequencies, where the former depends on the peak intensity, and the latter depends on not only the peak intensity but also the更多还原