用于超短脉冲CO2激光的半导体光开关理论建模与数值分析

本文开展了基于半导体光开关技术实现超短脉宽CO2激光输出的物理机制研究。首先,在分析光生载流子过程及载流子复合扩散机制的基础上,引入直接吸收、俄歇复合、等离激元辅助复合以及双极扩散等物理过程,并基于Drude理论,完善了半导体光开关理论模型。其次,利用该模型对两级半导体光开关产生超短CO2脉冲机制进行了数值模拟及分析,结果显示该模型与国外最新实验结果一致,表明了模型的合理性与正确性。最后,利用该模型分析了控制光脉冲宽度对两级光开关工作效率的影响,发现短的控制光脉冲更有利于精确、高效地截取出高质量的超短CO2脉冲。本文研究证明半导体光开关法是实现超短CO2激光脉宽可调输出的有效技术途径。

Modeling and numerical simulation of a semiconductor switching device applied in an ultra-short pulse CO2 laser

The physical mechanism are studied for ultra-short pulse CO 2 laser output realized by semicon-ductor switching technology.Firstly,based on the analysis of the generation,recombination and diffusion mechanism of laser-produced carriers,we introduce direct absorption,Auger recombination,plasmon-assisted recombination,an ambipolar diffusion process and according to Drude theory,we improve the theoretical model of semiconductor switching.Secondly,we simulate and analyze the generation of ultra-short CO 2 pulses by two-stage semiconductor optical switches employing this model.The results show that the model is in good agreement with the latest experimental results reported abroad,which implies the rationality and correctness of the model.Finally,the model is used to analyze the effect of control pulse duration on the efficiency of the two-stage switching.It is found that a short control pulse is more conducive to intercepting high-quality ultra-short CO 2 pulses accurately and efficiently.Semiconductor switching is an effective technique to realize the output of an ultra-short CO 2 laser with an adjustable pulse width.