利用800 nm抽运和400 nm探针技术，测量了CaF2和MgO的时间分辨反射率，研究了材料的电子激发和弛豫超快动力学过程。采用耦合动力学模型，探讨了飞秒激光对透明介质材料的激发，以及材料的激发对抽运激光在材料中的传输、分布和反射特性的影响。根据这个理论模型计算了时间分辨反射率的演化，计算结果和实验结果相吻合。研究表明，多光子电离(MPI)和碰撞电离(II)在介质材料的导带电子激发中起着重要的作用。

Using the 800-nm-pump and 400-nm-probe technique, the dynamics of the electron excitation and relaxation in CaF2 and MgO crystals was studied. A coupling model including both the multiphoton ionization (MPI) and the impact ionization (II) was applied to investigate laser propagation and conduction band electron production. The evolution of reflectivity was calculated, and the calculated results agree with the experimental results. The results indicate that both MPI and II play important roles in the generation of conduction band electrons. The relaxation dynamics was also discussed.