中文摘要：

通过数值求解一维含时薛定谔方程，本文研究了具有较长脉宽双色激光脉冲与氢原子模型相互作用产生的谐波辐射谱．研究发现，当采用12个光学周期的特定组合脉冲时，孤立阿秒脉冲可以实现．这里特定组合脉冲由两束类似频率脉冲（ω,ω＋δω）构成，附加脉冲的作用恰是调整基频光电场的形状．不同于入射基频光，整形后的基频光在时间始末端电场振幅被抑制，只有中间部分电场对谐波谱有贡献，它的作用等同于单一6飞秒超短脉冲的效果．从而扩展获得孤立阿秒脉冲所需脉宽从6飞秒到12飞秒．

英文摘要：

We investigate the high-order harmonic generation （HHG） spectra from hydrogen atom model exposed to the combined pulse with longer pulse duration, by numerically solving a one-dimensional time-dependent Schrodinger equation. It is shown that by adopting particular combined pulse with 12 optical cycles, single attosecond pulse can be obtained. The combined pulse is composed of two similar frequency pulses（ ω,ω＋δω ） and the role of additional pulse just modulates the electric field profile of fun- damental pulse. After shaped the beginning and end parts of electric field are suppressed drastically and middle part of electric field make a contribution to harmonic spectrum. So by this scheme, we extend the duration of driving pulse from 6fs to 12fs to generate single attosecond pulse.