采用单温模型，利用有限元方法对硅在纳秒脉冲激光作用下的温度积累效应进行了数值模拟。给出了单脉冲、多脉冲作用下，硅表面附近的非平衡载流子浓度、自由载流子吸收系数和晶格温度随时间的变化规律。结果表明，自由载流子浓度的积累是温度积累的主要来源。对于多脉冲作用情况，脉冲间隔越短，脉宽越窄，温度积累效应越明显，最终形成的瞬时晶格最高温和温升值越大，越容易对材料造成损伤。

The single-temperature model and Finite Element Method(FEM) are employed for the numerical simulation of the accumulative photo-thermal effect in silicon under illumination with sequential laser pulses. The time dependences of non-equilibrium carriers’ density, free carrier absorption, and the lattice temperature under the interaction with one pulse, and multiple-pulse are studied, as well as the optical damage threshold. The results show that the accumulation of free carrier concentration is the main source of temperature accumulation. In the case of multiple-pulse, the shorter the pulse interval, and the narrower the pulse width, the more easily the material can be damaged.