在经典的双温模型中引入电子激发、载流子吸收等电离过程，建立了飞秒激光和晶体材料相互作用的理论模型。采用有限差分法数值模拟了在飞秒激光作用下，不同掺杂摩尔分数的MgO∶LiNbO3晶体内电子、晶格温度随飞秒激光脉宽、激光能量密度的变化规律。并定量分析了不同掺杂摩尔分数的MgO∶LiNbO3晶体材料的损伤阈值随脉宽的变化规律，以及掺杂浓度对晶体损伤阈值的影响。结果表明，在LiNbO3晶体中掺入适量的MgO 将使载流子迁移率发生变化，进而会影响晶体的损伤阈值。在适当掺杂范围内，掺MgO 的摩尔分数越高，载流子迁移率越大，晶体的损伤阈值越高。因此，实际应用中可通过在LiNbO3晶体中掺入适量的MgO来提高晶体的抗损伤能力。

The theoretical model of the interaction between femtosecond lasers and crystal materials is established, in which the effects of electron excitation, carrier absorption and other ionizing process are coupled into the classical double-temperature model. The variations of the electron and lattice temperature with the pulse duration and fluence of femtosecond lasers in MgO∶LiNbO3 crystals with different doping concentration are numerically simulated by the finite-difference method. Furthermore, the variation of damage threshold with the femtosecond pulse width and influence in different doping concentration MgO∶LiNbO3 crystals, as well as the influence of doping concentration on damage threshold are analyzed quantitatively. Results show that, in appropriate doping range, with relatively higher MgO-doped concentration, the carrier mobility of MgO∶LiNbO3 crystals increases, and the damage threshold of the crystals becomes higher. Consequently, the resist damage capability of LiNbO3 crystal may be raised by appropriate MgO doping in practical applications.