激光驱动拉伸氢分子产生阈下谐波中拉比振荡特征的取向依赖

Alignment dependence of Rabi-flopping signatures in the below-threshold harmonics from the stretched H 2 driven by lasers

通过数值求解二维模型分子在强激光场中的含时薛定谔方程,研究了拉伸氢分子产生阈下谐波中拉比振荡特征的取向依赖.结果表明,三次谐波附近展现出精细次峰结构,借助于两态模型,将这些次峰结构归因于基态和第一激发态之间强耦合引起的拉比振荡.文中还发现这些次峰结构对分子取向角有很强的依赖,且次峰结构随着取向角(0°~90°)的增大而逐渐消失,这是由两态间的耦合强度随取向角增大而减小所引起.

We investigated the alignment dependence of Rabi-flopping signatures in the below-threshold harmonic generation from the stretched hydrogen molecules by numerically solving the two-dimensional time-dependent Schr dinger equation of molecules in laser fields.We found that fine sub-peaks near the third order harmonic and these fine sub-peaks can be attributed to Rabi oscillations originated from the strong-coupling between the ground state and the first excited state by using the two-state model.We also found that these fine sub-peaks strongly depend on alignment angles of molecules and gradually disappear as the alignment angle(0°~90°)increases because the coupling strength between these two states decreases with the alignment angle increasing.