强场高次谐波时间特性的理论分析

Time Profiles of High-Order Harmonic Spectra with High Intensity Laser Field

通过用单电子近似求解含时薛定谔方程 ,用加窗傅里叶分析的方法 ,分析了单原子产生的高次谐波的时间特性。理论分析表明 ,基态粒子数消耗对不同级次谐波辐射的影响程度不一样 ;谐波辐射随着入射激光场强度的增加会出现饱和 ;随着谐波级次的增加 ,谐波辐射越来越趋向于集中在更短的时间间隔内 ,相应的线宽也随着谐波级次的增加而增加。

High order harmonic spectra are obtained by numerically solving the one dimensional time dependent Schrodinger equation with single active electron (SAE) approximation. The time profiles of the harmonic spectra from a single atom are obtained through a Gabor analysis of the acceleration of the atomic dipole. The dependency of the different harmonics on the ground state population is investigated. It is shown that the harmonic yield tends to be saturated when driving laser is getting more and more intense, and that the harmonic radiation tends to be concentrated in a shorter interval when the harmonic order is getting higher, resulting in wider spectrum width.