论文部分内容阅读
利用光电导体产生太赫兹电磁波(THz波),THz远场辐射波形与光电导体材料的载流子寿命、偏置电场以及触发光有直接关系.用不同方法对低温GaAs(LT-GaAs)和半绝缘GaAs(SI-GaAs)光电导开关辐射的THz电磁波所呈现的双极特性进行了模拟计算.结果表明,LT-GaAs光电导开关辐射THz波呈现双极性的主要原因是光生载流子寿命小于一个THz波产生时间;而光生载流子寿命大于100ps的SI-GaAs光电导开关,在不同的实验条件(不同偏置电场、不同光脉冲能量)下,产生的THz波呈现双极特性的主要原因分别是载流子发生了谷间散射和空间电荷电场屏蔽.
The terahertz electromagnetic wave (THz wave) is generated by the photoconductor, and the far-field radiation waveform of the THz is directly related to the carrier lifetime, the bias electric field and the trigger light of the photoconductor material. The bipolar characteristics of the THz electromagnetic wave radiated by the photoconductive GaAs (SI-GaAs) photoconductive switch are simulated.The results show that the main reason for the bipolarity of the THz wave radiated by the LT-GaAs photoconductive switch is the photo-carrier lifetime Less than one THz wave generation time; and the SI-GaAs photoconductive switch with photogenerated carrier lifetime greater than 100 ps exhibits bipolar characteristics under different experimental conditions (different bias electric fields and different optical pulse energies) The main reason is the occurrence of the carrier scattering between the valley and space charge electric field shielding.