双色激光场驱动原子产生太赫兹辐射相关电子动力学研究

项目名称： 双色激光场驱动原子产生太赫兹辐射相关电子动力学研究

项目编号： No.11204375

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 周兆妍

作者单位： 中国人民解放军国防科学技术大学

项目金额： 24万元

中文摘要： 本项目拟采用剩余电流密度模型对太赫兹辐射进行数值模拟，通过数值求解真实原子体系的含时薛定谔方程，对激光作用时间内电子的剩余电流，即等离子体以太赫兹频率震荡的初始动力，进行计算。太赫兹辐射强度正比于剩余电流密度的平方。与直接用量子模型计算太赫兹辐射谱相比，该方法不需要在程序中计算皮秒量级以获得太赫兹精度的相干辐射谱，在保证太赫兹辐射精确计算的基础上大大提高了计算效率。该模型中，太赫兹辐射正比于电离电子空间速度分布的不对称性，基于该机制，我们将着重研究电子在双色激光场中的动力学行为，改变激光相位、强度、脉宽等特征，观察新的物理现象和效应。并将太赫兹辐射与高次谐波、阈上电离等强场物理现象相联系，对其相应动力学行为进行定量描述并丰富强场中的电子的动力学图像。

中文关键词： 太赫兹；高次谐波；阈上电离；双色场；重散射

英文摘要： The terahertz(THz) emission is simulated with the model of the residual current density (RCD) excitation in the interaction of the laser field and the atom. We can get the residual current, which is the initial impetus to plasma excitation of transverse dipole oscillationa with THz frequencies, by solving the time-dependent Schr?dinger equation. The THz intensity is proportional to the square of the RCD. Comparing to the direct calculation of THz emission spectrum based on the quantum calculation, this is still the ab initio model with the same veracity. While the calculation efficiency is enhanced a lot, because the pico-seconds interaction calculation, which is much longer than the duration of the laser pulse, is not necessary to get the coherent emission spectrum in THz precision. In the RCD model, the asymmetry of the velocity of the ionized electron is the key reason for the THz emission. We constrate on the dynamics of the electron in strong two-color laser field, which is a usual way to strengthen the THz emissions. The new physical phenomena and effects can be observed by adjusting the relative phase, intensity and the phase duration of the two-color laser fields. Besides, the THz emission dynamics can be connected to the other strong-filed phenomena such as the high-order harmonic generation (HHG) an

英文关键词： terahertz；high-order harmonics；above-threshold ionization；two-color field；rescattering