束缚态在高次谐波辐射中的作用分析

Analysis on Role of Bound States in High-Order Harmonic Generation

利用模型势构造了7种具有不同束缚态结构的原子模型,运用伪谱-劈裂算符方法计算了含时Schr dinger方程,从而得到了各种模型的高次谐波谱.通过提取高次谐波辐射中涉及到束缚态的跃迁成分,研究了束缚态在高次谐波辐射中的作用.计算结果表明,连续态-基态的跃迁对高次谐波辐射的贡献占主要地位,连续态-非基态束缚态以及束缚态-束缚态的跃迁可以有限的提高低阶谐波的强度,当束缚态数目较多时,束缚态之间产生共振跃迁的几率增大,从而可以进一步提高低阶谐波的强度,高能级束缚态的存在还可以增加连续态-基态的跃迁几率,从而在一定程度上提高整体的谐波强度.

Seven models with different structures of bound states are constructed by using several model potentials. Time-dependent Schrodinger equation is solved with pseudospectrum-split operator method to get the power spectra of seven models. The component of transactions referring to bound states is extracted to study the role of bound states in high-order harmonic generation. The results show that continuum-ground transaction plays dominant role in harmonic generation, whereas continuum-bound transactions, bound-bound transactions and resonance among bound states could enhance the intensities of harmonics in low-frequency region. In addition, the existence of bound states could add to the possibilities of continuum-ground transactions and then enhance the intensities of harmonics in plateau region.