高频激光脉冲作用下原子的光子和光电子发射

Photon and photoelectron emission of the atom under the action of high-frequency laser pulse

通过数值求解含时薛定谔方程,研究了原子在高频激光作用下的电离概率、光电子谱和谐波发射谱.研究发现,随着入射激光强度的增加,原子的电离概率逐渐增加,达到最大后下降,其光电子发射谱和高次谐波发射谱均由单峰结构变成多峰.而通过对谐波发射谱的时间-频率分析发现,在电离抑制区域,脉冲的峰值附近谐波受到抑制,谐波发射主要发生在上升沿和下降沿,二者的干涉效应产生了谐波的多峰值结构.利用光电子发射谱和谐波发射谱随入射激光强度的改变规律,可以实现对引起原子电离抑制的激光强度进行诊断.

By numerically solving the time-dependent Schr6dinger equation, we investigate the ionization probability, photo- electron spectrum, and harmonic emission spectrum of the atom under the action of high-frequency laser pulses. It is found that with the increase of incident laser pulse intensity, the ionization probability of the atom first increases to a maximum value gradually and then decreases, and in this process, both the photoelectron spectrum and high-order harmonic generation spectrum change from a single-peak structure to a multi-peak one. Through the time-frequency analysis of the harmonic emission spectrum, we also find that the harmonic emission is suppressed around the pulse peak, and it occurs at the rising edge and the falling edge, which interfere with each other, thus forming the multi-peak structure. Utilizing the laws of the changes of photoelectron and harmonic spectra with incident laser pulse intensity, we can diagnose the laser intensity at which the atomic ionization suppression occurs.