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利用超短激光脉冲触发光电导天线产生太赫兹波是目前研究比较深入,同时得到广泛采用的一种太赫兹波源。电流瞬冲模型能较好地解释光电导天线辐射太赫兹波的机理,并且与实验相吻合,因而被普遍接受。影响光电导天线的因素有材料性质、偏转电压、激光脉冲宽度和单脉冲能量等,其中激光脉冲宽度和激光脉冲能量对太赫兹辐射有很重要的影响。材料中的光生载流子寿命对辐射也有一定的影响。当改变这些参数时,辐射的太赫兹波有不同的特性变化。此外,逐步增大激光脉冲能量,会发现辐射的太赫兹波强度存在一个饱和特性。
The use of ultrashort laser pulses to trigger photoconductive antenna to generate terahertz wave is a kind of terahertz wave source which has been researched deeply and widely used at the same time. The current transient model can well explain the photoconductive antenna radiation terahertz wave mechanism, and consistent with the experiment, it is generally accepted. The factors affecting the photoconductive antenna are material properties, deflection voltage, laser pulse width and single-pulse energy, etc. The laser pulse width and laser pulse energy have important influence on terahertz radiation. The photo-generated carrier lifetime in the material also has some influence on the radiation. When these parameters are changed, the radiated terahertz waves have different characteristics. In addition, increasing the laser pulse energy gradually reveals that there is a saturation characteristic of the terahertz radiation intensity.