利用超短的紫外光源来增强阿秒脉冲的强度

摘要

A promising method to improve the attosecond pulse intensity has been theoretically presented with the assisted of an ultrashort ultraviolet pulse.It shows that by properly adding an ultrashort 62 nm or 125 nm ultravi-olet pulse to the synthesized two-color field, not only the harmonic cutoff but also the harmonic yield are re-markably enhanced compared with the original two-color field case.Especially for adding the 125 nm pulse case, the harmonic yield is enhanced by 2 orders of magnitude, and an ultrabroad 232 eV bandwidth is ob-tained.Finally, by superposing harmonics from the 113th to the 170th, an intense isolated pulse as short as 43 as can be directly produced, which is 2 orders of magnitude higher than the case of generation from the original two-color field.%本文理论提出了一种利用超短紫外光源来增强阿秒脉冲强度的方法。计算结果表明，当适当的加入一束62 nm或者125 nm超短紫外光源到双色激光场时，不仅高次谐波的截止能量被延伸了，而且谐波的强度也比原双色场时有明显的增强。尤其是当采用125 nm光源时，谐波的强度被增强了2个数量级，并且形成了一个232 eV的超长平台区。最后通过叠加谐波次数从113次到170次可获得脉宽仅为43 as的孤立阿秒脉冲，其强度比原双色场情况下产生的阿秒脉冲增强了2个数量级。