用太赫兹辐射观测和操控强场动力学

项目名称： 用太赫兹辐射观测和操控强场动力学

项目编号： No.11474359

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 张栋文

作者单位： 中国人民解放军国防科技大学

项目金额： 98万元

中文摘要： 半导体中电子-空穴碰撞产生的高阶太赫兹边带以及太赫兹脉冲在晶体中产生的高次谐波都表明强太赫兹场已经成为强场物理中一种新的量子操控手段。飞秒激光脉冲电离气体产生的单周期、载波包络相位稳定、偏振态可控的强太赫兹场，可以优化分子的取向、提高高次谐波的辐射效率、调制光电子的动量分布。本项目通过控制双色激光场的相位、光强、偏振、波长，同时测量原子和定向分子隧穿电离产生的太赫兹谱、高次谐波谱和光电子动量谱，实验研究库仑场在太赫兹辐射中的作用，刻画太赫兹辐射的近场空间分布，并用产生的强太赫兹场调制电子波包的动力学过程。项目结果有助于提高太赫兹辐射的效率，发展用太赫兹辐射去原位测量激光相位的技术，用太赫兹辐射对分子势成像的方法，实现从太赫兹波到X射线，对复杂量子态演化的多时间尺度的观测和全电磁波段的操控。

中文关键词： 高次谐波；阈上电离；分子取向；强激光场；原子分子物理

英文摘要： Intense terahertz field has become a new tool for the manipulation of quantum states in strong field physics, which has been demonstrated by the generation of high-order sidebands by electron-hole collisions of excitons in the semiconductor and high-order harmonics by Bloch oscillations in the crystal. The intense terahertz field with single-cycle, stabilized carrier-envelope phase and controlled polarization can be generated by the ionization of gas in the strong femtosecond laser field. This intense terahertz field can be used to optimize the orientation of molecules, enhance the efficiency of high-harmonic generation and modulate the momentum distribution of photoelectrons. This proposal will measure simultaneously terahertz radiation, high-order harmonics and above-threshold ionization of atoms and oriented molecules, which are tunnel-ionized with varying the relative phase, intensity, polarization and wavelength of the two-color laser field. The Coulomb effect on the terahertz radiation will be well studied and the spatial distribution of terahertz radiation in the near field will be carefully characterized. It emphasizes the manipulation of the dynamics of electronic wavepackets in the strong laser field using intense terahertz field. The achievement of this project will increase the efficiency of terahertz generation, develop the mew method to diagnose the phase of a laser filed in situ and to map molecular potentials, even realize the muti-time-scale manipulation of the complex evolution of quantum states using whole electromagnetic spectra covered from terahertz to X-ray.

英文关键词： high harmonics;above threshold ionization;molecular alignment;intense laseer field;atomic and molecular physics