利用两色红外组合场驱动氦原子产生单个阿秒脉冲

The single attosecond pulse generated by helium atom exposed to two-color combined laser field

利用数值求解原子在强激光场中的含时薛定谔方程,对一维氦原子处于两色红外组合场中产生的高次谐波进行了研究,研究发现,在组合场驱动下,谐波谱的截止位置可以拓展到Ip+5.7Up,从而得到脉宽较短的多个阿秒脉冲,通过改变两束激光的相位延迟,最终得到了33.8as的单个脉冲.进一步利用小波变换分析了阿秒脉冲的发射特征,发现单个阿秒脉冲实现是对电子长路径抑制的结果.

By solving the time-dependent Schr（o）dinger equation numerically,we study the high harmonics of one-dimensional He atom exposed to the combined field composed of two infrared laser pulses.It is shown that the harmonic spectrum is extended to Ip ＋ 5.7Up in the case of combined fields,thus we can obtain shorter trains of attosecond pulses.By adjusting the phase delay between the lasers,we can obtain an isolated 33.8 as pulse.Furthermore,analyzing the characteristic of generation of the attosecond pulse based on the wavelet transform,it is found that the contribution of the long electron trajectory on harmonic generation is suppressed,thus we can obtain the single attosecond pulse.