强激光场中极性分子奇偶谐波辐射的时间分辨动力学研究

项目名称： 强激光场中极性分子奇偶谐波辐射的时间分辨动力学研究

项目编号： No.11504069

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 张冰

作者单位： 哈尔滨工业大学

项目金额： 19万元

中文摘要： 强激光场中极性分子谐波辐射是目前强场物理的一个研究热点。由于对称破缺，极性分子的谐波辐射谱中一般包含奇偶谐波。目前对极性分子奇偶谐波辐射的研究主要集中在谐波功率谱，要深入了解奇偶谐波的复杂起源，需要研究其时间分辨动力学，而此项工作尚未见报道。本项目欲从理论上详细研究单色激光场辐射下，具有不同核间距的极性分子奇偶谐波辐射的时频特性，深入分析不同电离通道（基态通道和激发态通道）和谐波辐射通道（奇次谐波通道和偶次谐波通道）在时域上的竞争机制。通过对时域现象的研究，深入剖析极性分子电离与谐波辐射取向依赖的内在关系，两中心干涉效应和固有偶极矩效应之间的相互作用。此外，本项目还将研究双色场中极性分子的奇偶谐波辐射，探究激光场导致的奇偶谐波辐射与不对称的库伦势导致的奇偶谐波辐射之间的关系。这些研究将有助于人们理解极性分子的电离及谐波辐射机制，并为相关的实验研究提供有益的参考。

中文关键词： 高次谐波；遂穿电离；极性分子

英文摘要： The harmonic emission from polar molecules exposed to strong laser field is one hot topic in strong-field physics. Due to symmetry breaking, polar molecules emit both odd and even harmonics. Present studies mainly focus on the power spectra of odd-even harmonic emission from polar molecules. However, in order to understand the complex origin of the odd-even harmonic emission, the study of their time-resolved dynamics is desired. In this project, the time-frequency properties of the odd-even harmonic emission from polar molecules with diverse inter-nuclear distances in strong laser fields will be investigated theoretically. The competition mechanism in the time domain between different ionization channels (the ground state channel and the first excited state channel) and recollision channels (odd harmonic channels and even harmonic channels) will be deeply analyzed. From the time-frequency phenomena, the inner relation between orientation dependence of ionization and harmonic emission, the interaction between two-center interference and permanent dipole of the molecule are also studied. Moreover, we will study the odd-even harmonic emission from polar molecules in two-color laser field, with aiming at the relation between the laser-field induced odd-even harmonic emission and that arising from the asymmetric potential of the polar molecule. These studies will benefit understanding of ionization and harmonic emission mechanism and provide reference to the related experimental work.

英文关键词： high-order hamonic generation;tunneling ionization;polar molecule