偏振方向对ZnTe电光THz辐射探测的影响

EFFECTS OF PROBE-BEAM POLARIZATION DIRECTION ON THz DETECTION IN ZnTe

在实验上研究了探测光的偏振方向对ZnTe晶体THz探测的影响 .在一周 36 0°范围内 ,测量出现两次零值 ,角度间隔为 180° ,在两个零值之间的 90°处出现不为零的小值 ,4 5°处不为最大值 .将ZnTe晶体在THz辐射电脉冲作用下产生的电光效应等效于瞬间任意波片 ,用琼斯矩阵法模拟实验过程 ,结果表明除在 90 0 处出现零值外其余模拟结果与实验结果相符 .用THz光子与横光学声子相互作用模型对此进行了定性解释 .

The effects of probe-beam polarization direction on the THz detection in ZnTe were investigated experimentally. By keeping the THz radiation intensity unchanged, we observed two minimums with an interval of 1800 when the direction of the probe-beam polarization theta was changed from 0 to 360degrees. Non-zero THz radiation was detected in the middle of the two minimums ( theta = 90degrees). The Jones Matrix method was employed to simulate the experiments by assuming the electro-optic effect in ZnTe under a THz field as-an equivalent arbitrary wave plate. It was found that all the simulation results were in agreement with the experiments, except for theta = 90degrees. A qualitative explanation based on the interaction between THz photons and TO phonons was presented.