HeH2+分子谐波辐射的空间分布
Spatial distribution of molecular harmonic generation from HeH2+

理论研究了HeH2+分子发射高次谐波的空间分布情况。结果表明：分子谐波发射主要集中在He核和H核附近。当核间距离较小时，He核辐射谐波强度要比H核辐射谐波强度高2~3个数量级。当核间距离较大时，He核辐射谐波强度要比H核辐射谐波强度高4~5个数量级。当空间非均匀激光场引入后，谐波截止能量得到延伸，并且，随着空间非均匀激光场位置由负向到正向移动(-100 a.u.到100 a.u.)，谐波截止得到进一步延伸。但是He核辐射谐波强度依然大于H核。最后，通过叠加谐波可获得脉宽在60 as的超短脉冲。
Spatial distribution of the harmonic generation from HeH2+ has been theoretically investigated. It shows that the molecular harmonic emissions mainly occur around the He and the H nuclei. At smaller internuclear distance, the harmonic intensity from the He nucleus is 2~3 orders of magnitude higher than that from the H nucleus. At larger internuclear distance, harmonic intensity from the He nucleus is 4~5 orders of magnitude higher than that from the H nucleus. With the introduction of the spatial inhomogeneous laser field, the harmonic cutoff is extended. Moreover, as the spatial position of the inhomogeneous field moving from the -100 a.u. to the 100 a.u., the harmonic cutoff can be further enhanced. But, the harmonic intensity from the He nucleus is still higher than that from the H nucleus. Finally, by properly selecting particular harmonics orders, an ultrashort 60 as pulse can be produced.