空间非均匀场下核间距对不对称分子谐波发射的影响

Internuclear distance effect on asymmetric molecular harmonic generation in the present of spatial inhomogeneous fiel

数值研究了空间非均匀场下核间距离对于不对称分子HeH^(2+)发射高次谐波以及阿秒脉冲的影响.计算结果表明,通过适当调节HeH^(2+)分子离子的核间距离以及空间非均匀参数,不仅谐波发射的截止能量得到了延伸,而且单一的短量子路径也被选择出来对谐波发射起作用.随后适当引入第二束控制激光场,谐波截止能量得到了进一步扩展,形成了两个带宽分别在431 eV和372 eV的连续平台区.最后,通过适当的叠加谐波,可获得脉宽为31 as-65 as的一系列阿秒X射线光源.

We theoretically investigate the internuclear distance effect on the generations of the molecular high-order harmonics and the attosecond pulses when HeH2＋ is exposed to the spatial inhomogeneous laser field. The results show that by properly choosing the internuclear distances and the spatial inhomogeneous parameters of the fundamental pulse, not only the harmonic cutoff is remarkably enhanced, but also the single short quantum path is selected to contribute to the harmonic emission. Further, with the introduction of the second controlling pulse, the harmonic cutoff has been further extended, leading to two supercontinua with the bandwidths of 431eV and 372eV. Finally, by properly superposing the selected harmonics, a series of attosecond X-ray pulses with the durations from 31as to 65as can be obtained.