光激发非平衡载流子的瞬态输运及强THz辐射研究

Research of High Peak Power Terahertz Radiation and Transient Transport Process of Light Stimulates Non-equilibrium Carriers

对强偏置电场作用下砷化镓光电导偶极天线的太赫兹辐射特性进行实验和理论研究,对比分析开关天线体内非平衡载流子的瞬态输运特性。结果发现:强电场下热电子平均漂移速度的变化与弱场情况具有显著的不同,初始阶段小角度光学波极化势散射表现出极大的优势,载流子以近弹道运动的方式被加速,瞬变漂移速度上升陡峭并导致速度过冲是产生强THz辐射的主要原因。

The characteristic of terahertz radiation from Ga As photoconductive dipole antennas with an ultrahigh electric fields are discussed; the transient transport properties of non-equilibrium carriers within the photoconductive switches antenna are comparatively analyzed. It is shown that there are significant differences in the average drift velocity variation with strong and weak electric field. In the initial phase,optical wave scattering is mainly caused by small-angle scattering,carriers are accelerated by ballistic transport to reach higher electron energy in a shorter time,and the transient drift-velocity quickly rises,which is a main reason of the stronger THz radiation.