不均匀场中氢分子离子高次谐波产生的理论研究

摘要

High-order harmonic generation from hydrogen molecular ion in the inhomogeneous laser field is studied theoretically by numerically solving the non-Born-Oppenheimer time-dependent Schrdinger equation.The results show that ionized electrons can acquire more accelerating energy in inhomogeneous laser field than in homogeneous field, which is beneficial to generate a broader supercontinuum.Furthermore, by optimizing spatial non-uniformity of the inhomogeneous field, the long quantum path is suppressed obviously, and an isolated 60-as pulse is achieved by superposing harmonics from 110th to 150th orders.Besides, combined Coulomb and laser field potential as well as time-frequency distributions are applied to illustrate the physical mechanism.%在非Born-Oppenheimer近似下,通过求解含时薛定谔方程的方法,对氢分子离子在不均匀场中高次谐波的产生进行了理论研究.计算结果显示,同均匀场相比,电离的电子在不均匀场中加速会获得更多的能量,从而更有利于得到宽频谱.此外,通过优化不均匀场中的空间不均匀度,长量子路径被明显的抑制,最终通过叠加110阶到150阶谐波,获得一个60as的孤立阿秒脉冲.同时,通过库仑势和激光场的相互作用势以及时频分布图解释了其中的物理机制.