Ito Hironori, Nakano Tetsuo, Nomura Shintaro, Misawa Kazuhiko
Opt Express. 2019 Sep 30;27(20):28091-28103. doi: 10.1364/OE.27.028091.
In this study, we demonstrate the switching of the direction of the photocurrent in an n-type GaAs/AlGaAs modulation-doped quantum well using a polarization pulse-shaping apparatus containing a 4f setup. The right- and left-polarization-twisting pulses with a polarization rotation frequency in the THz-regime are incident on a modulation-doped quantum well. The results show that the sign of the photovoltage is dependent on the direction of rotation of the polarization-twisting pulses, which can be explained by the circular photogalvanic effect combined with the production of a classical edge photocurrent from the acceleration of free electrons in the vicinity of the sample edge by the incident optical electric field. The wide range over which the polarization-rotation frequency may be tuned makes this method a powerful tool to investigate the response of an extensive variety of materials in the THz-regime.
在本研究中，我们使用包含4f装置的偏振脉冲整形装置，展示了在n型GaAs/AlGaAs调制掺杂量子阱中光电流方向的切换。具有太赫兹频段偏振旋转频率的右旋和左旋偏振扭曲脉冲入射到调制掺杂量子阱上。结果表明，光电压的符号取决于偏振扭曲脉冲的旋转方向，这可以通过圆光电流效应结合由入射光电场在样品边缘附近加速自由电子产生的经典边缘光电流来解释。偏振旋转频率可调节的宽范围使得该方法成为研究太赫兹频段各种材料响应的有力工具。
