高次谐波发射中的超拉曼发射

摘要

We investigated high harmonic generated from the interaction of intense pulses with a one-electron model molecular ion. When the intensity of the laser pulse is weak,the hyper-Raman (HR) lines are observed clearly. With the increase of the laser intensity, the HR lines only appeared as the background of high harmonic generation (HHG) due to its weak intensity. This phenomenon is attributed to the various roles of excited states in the different laser intensity. To observe the HR lines in the experiment, it is necessary to prepare a superposition states by adding an additional long laser pulse.%本文研究了单电子分子离子与强激光场相互作用下的高次谐波发射谱.从光谱中观察到除了存在入射激光频率奇数倍的谐波谱线外,还存在其他频率的超拉曼谱线.在理论上阐明了超拉曼谱线不同于高次谐波谱线的物理产生机制.研究发现当体系初态为基态和较高激发态的叠加态时能够较清晰的观察到超拉曼谱线,从而说明激发态电子的布居对超拉曼谱线的产生起着关键作用.因此在实验上,制备一个叠加态使得电子从激发态电离,是观察到超拉曼谱线的重要条件.