Data supporting: "Versatile and Active THz Wave Polarization Modulators Using Metamaterial/graphene Resonators"

Active modification of the polarization state is a key feature for the next-generation of wireless communications, sensing, and imaging in the THz band. The polarization modulation performance of an integrated metamaterial/graphene device is investigated via a modified THz time domain spectroscopic system. Graphene’s Fermi level is modified through electrostatic gating, thus modifying the device’s overall optical response. Active tuning of ellipticity by >0.3 is reported at the resonant frequency of 0.80 THz. The optical activity of transmitted THz radiations is continuously modified by >21.5deg at 0.71 THz. By carefully selecting the transmitted frequency with the relative angle between the incoming linear polarization and the device’s symmetry axis, active circular dichroism and optical activity are almost independently exploited. Finally, this all-electronically tuneable versatile polarization device can be used in all applications requiring an ultrafast modulation such as polarization spectroscopy, imaging, and THz wireless generation.Description

偏振态的主动调控是太赫兹（THz）频段下一代无线通信、传感与成像技术的核心特征之一。本研究通过改进型太赫兹时域光谱系统，对集成超材料/石墨烯器件的偏振调制性能开展了实验表征与分析。通过静电栅极调控可改变石墨烯的费米能级（Fermi level），进而调控器件的整体光学响应。在0.80 THz的谐振频率处，可实现椭圆率调控幅度大于0.3的主动调谐。在0.71 THz频段，透射太赫兹辐射的光学活性可被连续调控，调控幅度超过21.5°。通过选取合适的透射频率，并调节入射线偏振光与器件对称轴的相对夹角，可近乎独立地实现圆二色性（circular dichroism）与光学活性的主动调控。最终，这款全电控可调谐的多功能偏振器件可应用于所有需要超快调制的场景，例如偏振光谱学、成像以及太赫兹无线信号生成等领域。