The dynamics of produced excited carriers under the irradiation of Ge crystal is investigated theoretically by using femtosecond laser pulse. A two-temperature model combined with the Drude model is also used to study the nonequilibrium carrier density, carrier and lattice temperatures, and optical properties of the crystal. The properties of the surface plasmon wave when excited are also studied. The influences of non-radiation and radiative recombination process on the photoexcitation of the semiconductor during pulse and the relaxation after the pulse are described in detail. The results show that the effects of Auger recombination on the nonequilibrium carrier density and optical properties of the crystal and the properties of the surface plasmon polariton are great, whereas the effect of radiative recombination is extremely small.

利用飞秒激光脉冲从理论上研究了Ge晶体辐照下产生的激发载流子的动力学。结合 Drude 模型的双温度模型也用于研究晶体的非平衡载流子密度、载流子和晶格温度以及光学性质。还研究了激发时表面等离子体波的特性。详细描述了非辐射和辐射复合过程对半导体在脉冲过程中的光激发和脉冲后弛豫的影响。结果表明，俄歇复合对晶体的非平衡载流子密度和光学性质以及表面等离子体激元性质的影响很大，而辐射复合的影响极小。