| 题名 | 高次谐波转换效率的提高和谐波扩展的理论研究 |
| 作者 | 陈静 |
| 学位类别 | 硕士 |
| 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 | 强场物理 超短强激光 谐波扩展 |
| 其他题名 | Theoretical study on efficiency improvement of high-harmonic generation and harmonic extension |
| 中文摘要 | 该论文通过数值求解一维薛定谔方程,对如何提高高次谐波的转换效率和获得更高级次(更短波长)的谐波辐射展开了理论研究,取得了以下几点创新性研究成果:第一,利用基频光及一非常弱的辅助高倍频光(9倍、13倍甚至120倍频光等)形成的双色场(该场高频光强度仅为基频光的百分之一)作用于氦离子He<'+>,我们对加入不同的低强高频光对双色场高次谐波产生的影响进行了数值模拟.结果发现高次谐波谱的转换效率有了普遍提高,尤其是相应于入射高频光频率对应级次及邻近级次有很大提高,可增强约7个数量级,甚至更高.另外还对其物理机制进行了初步阐释.第二,针对超短强激光与线状多原子分子离子相互作用产生的高次谐波进行研究,发现了通过调节适当的激光初始相位可以大大改善高次谐波谱的分辨率.通过进一步计算,给出了初步解释.这一结果增进了对超短强激光与多原子系统相互作用的理解,对进行二维模拟研究以及具体实验也有参考作用.第三,我们还发现了只要原子核间距大于增强电离所在的范围,高次谐波辐射的截止能量就可以达到、甚至超过Ip+8Up.这增加了获得更短波长的机会.以上研究成果均已被国内核心学术期刊发表和接受. |
| 英文摘要 | In latest ten years, ultra-short strong laser technology has acquired tremendous progress, which makes it possible to investigate laser-matter interaction under extreme conditions and paves the way to discovery and exploration of brand-new physical phenomena. High-harmonic generation in strong field has attracted many scientists' attention due to its latent wide use, and has been achieved rapid progress in this area. To acquire harmonics with shorter wavelength and improve the efficiency of high-harmonic generation becomes one of the main directors in the intense laser field study. How to improve the harmonic efficiency and acquire shorter wavelength is the main subject of this dissertation. It has been investigated theoretically by means of one-dimension numerical simulations. The main results are as follows: The first, we calculated the high-harmonic generation for Helium ion He+in a two-color field, which is composed of a driving field and a weak subsidiary high frequency field (Is = I_0/100 , (ω,13ω),... (ω,120ω)). We calculated the different effects coming from the different subsidiary fields and found that such field can produce much higher harmonic intensity, typically increasing the harmonics corresponding to the incident frequency of the subsidiary field. Harmonics were enhanced by about 7 orders or more of magnitude comparing to harmonics generated from single-color field. Additionally, a primary explanation of its physical mechanics was given. Secondly, we calculated the high-order harmonic generation from linear multi-atom molecular ion in an ultra-short laser field. We found that phase matching of HHG could be improved, or well defined harmonics could be produced by properly adjusting the initial phase of laser field. On second study, we gave a rudimental explanation. This conclusion gave a deeper understanding on the interaction between multi-atom system and ultra-intense-ultra-short laser field. It also could be applied to other theoretical and experimental study. At last, it was found that the cut-off energy could get or even exceed Ip+8Up when inter-nucleus distance beyond the range of enhanced ionization. This finding offered a new opportunity to obtain new light source with shorter wavelength, which owned important practical value. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16616]  |
| 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 | 陈静. 高次谐波转换效率的提高和谐波扩展的理论研究[D]. 中国科学院上海光学精密机械研究所. 2002. |
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