空间非均匀激光场下He原子辐射谐波的量子路径调控

Quantum path control on the harmonic emission from He atom driven by the spatial inhomogeneous laser field

摘要:

理论研究了He原子在空间非均匀激光场下辐射谐波的量子路径调控。计算结果表明，随着空间非均匀激光场引入位置由负向-r0到正向-r0移动，谐波截止能量呈单调递增趋势，而且只有单一的短量子路径对最大谐波辐射过程起作用。通过分析谐波辐射时频分析图和电子含时波包演化图，对谐波辐射的特点给出了合理解释。随后适当引入一束太赫兹激光场，谐波强度被增强2个数量级，并且形成一个1208eV的超长平台区。最后，通过叠加谐波，可获得一系列持续时间在34 as的超短脉冲，其波段覆盖为10 nm~1 nm。

Abstract:

Quantum path control on high-order harmonic generation (HHG) from He atom by the spatial inhomogeneous laser field has been investigated. Results show that with the introduction of the spatial inhomogeneous field from the negative-r0 direction to the positive-r0 direction, a monotone enhancement of the harmonic cutoff is obtained and there is only the single short quantum path contributing to the maximum harmonic emission event. Time-frequency harmonic distributions and the time-dependent wave function have been shown to explain the harmonic spectra. Further, by properly adding a THz field, the harmonic intensity is enhanced by 2 orders of magnitude, and a smooth 1208 eV super-bandwidth can be obtained. Finally, by properly superposing the harmonics, a series of isolated 34 as pulses with wavelengths from 10nm to 1nm can be obtained.