Actively tunable ultrafast broadband terahertz (THz) polarimetry using a reconfigurable phase‐change material holds great potentials and prospects for the achievement of next‐generation versatile integrated THz components and systems in a variety of THz applications. Here, an optically tunable ultrafast broadband THz polarimetric device (THz‐PoD) composed of a phase‐change material Ge2Sb2Te5 (GST) and a thin mica substrate is demonstrated. This proposed novel THz‐PoD is verified for a frequency range of 0.1–2.5 THz, exhibiting broadband and ultrafast determination of polarization states for linearly polarized THz waves at polarization angles from −90° to 90°. It is shown that optical excitation with ns pulses allows easy and efficient control of the polarimetric properties of such THz‐PoD. The essential role of the GST film in switching the phase transition between the amorphous and crystalline phases is emphasized by the theoretical investigation of the optically tunable ultrafast polarimetric mechanism of the device. This phase transition allows optically changing the THz‐PoD's properties by ns‐pulsed laser in a controlled way to achieve THz polarimetry for linearly polarized THz waves. The combined advantages of this strategy can open up a new and promising way for realizing versatile reconfigurable and integrated THz devices, which may further promote the development of novel THz systems and applications.

中文翻译：

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使用非易失性相变材料的光学可调谐超快宽带太赫兹偏振装置

使用可重构相变材料的主动可调谐超快宽带太赫兹（THz）偏振测量对于在各种太赫兹应用中实现下一代多功能集成太赫兹组件和系统具有巨大的潜力和前景。这里，由相变材料Ge组成的光学可调谐超快宽带太赫兹偏振装置（THz-PoD）2锑2碲5演示了（GST）和薄云母基板。这种提出的新型 THz-PoD 在 0.1-2.5 THz 的频率范围内进行了验证，表现出宽带和超快速确定偏振角从 -90° 到 90° 的线偏振太赫兹波的偏振态。结果表明，纳秒脉冲的光学激发可以轻松有效地控制此类 THz-PoD 的偏振特性。通过对该器件的光学可调超快偏振机制的理论研究，强调了 GST 薄膜在非晶相和结晶相之间切换相变中的重要作用。这种相变允许通过纳秒脉冲激光以受控方式光学改变太赫兹-PoD的特性，以实现线偏振太赫兹波的太赫兹偏振测量。该策略的综合优势可以为实现多功能可重构和集成太赫兹设备开辟一条新的、有前途的途径，这可能会进一步促进新型太赫兹系统和应用的发展。