半绝缘GaAs光电导开关产生太赫兹波电场屏蔽效应的二维Monte Carlo模拟  

Two-dimensional Monte Carlo simulation of screening of the bias field in terahertz generation from semi-insulated GaAs photoconductors

作　　者：贾婉丽[1] 纪卫莉[1] 施卫[1] 

机构地区：[1]西安理工大学理学院,西安710048

出　　处：《物理学报》2007年第4期2042-2046,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10390160;10376025;50477011);国家重大基础研究专项基金(批准号:2004CCA04500G).~~

摘　　要：利用Ensemble-Monte Carlo模拟方法,对不同实验条件下半绝缘GaAs(SI-GaAs)光电导开关作为偶极辐射天线在辐射太赫兹电磁波(太赫兹波)中体内电场的分布以及空间电荷屏蔽效应对太赫兹波辐射的影响进行了模拟.载流子的时域空间电场分布表明:用高能量激光脉冲触发低压偏置的GaAs开关,空间电荷屏蔽是限制太赫兹波辐射功率的一个重要因素,并且空间电荷屏蔽能够引起太赫兹波呈现双极性.当高能量飞秒激光脉冲以全电极间隙触发大孔径光电导天线时,空间电荷电场屏蔽效应对太赫兹波的影响不大.Ensemble-Monte Carlo model is used to simulate the time-resolved spatial electric field distribution and the influence on terahertz emission by screening of the bias field by the space charge in semi-insulated GaAs （SI-GaAs） photoconductive switches under different experimental conditions. The time-resolved spatial electric field distribution of photo-generated carriers shows that space charge screening is one of the important factors that limit high-power terahertz radiation of the biased SI-GaAs photoconductors triggerd by high optical energy pulses, and space charge screening can produce bipolar terahertz waveforms. When large-aperture biased photoconductors are triggerd by uniform gap illumination of high optical energy pulse, the effect of space-charge screening on terahertz radiation is small.

关 键 词：光电导开关 Ensemble-Monte CARLO模拟 辐射场屏蔽 空间电荷屏蔽 

分 类 号：TN25[电子电信—物理电子学]