周期量级超短脉冲激光与二能级原子系统的非线性相互作用
文献类型：学位论文
| 作者 | 肖健 |
| 学位类别 | 博士 |
| 答辩日期 | 2002 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 徐至展 |
| 关键词 | 面积定理 自感透明 自相位调制 拉比振荡 超短脉冲激光 |
| 其他题名 | The Nonlinear Interaction of Few-cycle Ultrashort Pulse Laser with Two-Level Atom System |
| 中文摘要 | 目前,周期量级超短脉冲激光与原子、分子的相互作用已经成为光与物质相互作用的最新研究热点.该论文系统进行了周期量级超短脉冲激光在二能级原子系统传播中的面积演化、连续谱产生等非线性过程的基础研究.取得的主要创新成果如下:1.理论上进一步证明了慢变振幅近似与旋转波近似方法对描述超短脉冲传播的局限性.周期量级超短脉冲的电场导数项能使介质的粒子数分布产生振荡,介质折射率、脉冲快速振荡成分的产生与载波的振荡密切相关,从而证明传统的近似方法和面积定理对描述超短脉冲传播的局限性;同时发现脉冲的分裂、压缩和展宽都与介质的粒子数分布有关.2.首次发现了周期量级超短脉冲激光传播中面积演化的新规律.3.首次发现了周期量级超短脉冲激光的自感透明消失的现象和宽带的频谱转换.4.首次研究了周期量级超短脉冲激光在共振的二能级原子系统中的载波与相应的光谱对初始相位的依赖性. |
| 英文摘要 | The interaction of few-cycle ultrashort pulse laser with atoms and molecules is currently being an hot subject in the research of the light-matter interaction. In this thesis, we make a fundamental research on the area evolution, the generation of the super-continuum, and other nonlinear process of the few-cycle pulse laser propagating in the two-level atom system systematically. The main innovative results are as follows: We make a further demonstration theoretically about the limitation of the standing slowly varying envelope approximation and the rotating-wave approximation to describe the propagation of the ultrashort pulse. The time-derivative term of the electric field of the ultrashort pulse may lead to oscillatory feature of the population distribution, the refractive index of the medium and the generation of fast oscillatory components of the pulse are closely connected with the oscillatory carrier field, thus the traditional approximations and the area theorem are fail to describe the ultrashort pulse propagation. Furthermore, the pulse splitting, the pulse compression, and the pulse broadening are all related with the population distribution of the medium. A new kind of area evolution of the few-cycle pulse laser propagating in the two-level atom system is firstly reported. Although the traditional area theorem cannot describe the ultrashort pulse propagation accurately, it can still predict the profile of the area evolution of few-cycle optical pulse. Because the few-cycle pulse is very short, the variation of the pulse area is caused by the pulse splitting but not by the pulse broadening or the pulse compression as in the long pulse cases. The area evolution of two coherent few-cycle pulses is also consistent with the area theorem, while their propagation is closely connected with their relative phase and the pulse separation. We firstly found that the ideal self-induced transparency of few-cycle pulse disappears and extreme broadband frequency conversion occurs. The carrier wave effects, including the carrier wave self-phase modulation, the carrier-wave Rabi flopping, and the intrapulse four-wave mixing, become the main mechanism in the spectral modification, in this case, the ideal self-induced transparency of few-cycle pulse disappears. And for large pulse area, extreme broadband frequency conversion occurs, the corresponding spectral plateau supports the generation of lfs pulse. The phase-dependent feature of few-cycle ultrashort pulse laser propagating in the two-level atom medium is demonstrated for the first time. For few-cycle pulse laser, different initial phases result in different carrier intensities and different carrier effects. So that even in the perturbative region, the propagation of few-cycle pulse laser will also show evident sensitivity to the initial phase. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15572]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 肖健. 周期量级超短脉冲激光与二能级原子系统的非线性相互作用[D]. 中国科学院上海光学精密机械研究所. 2002. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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