Terahertz (THz) pulses are applied in areas as diverse as materials science, communication and biosensing. Techniques for subwavelength concentration of THz pulses give access to a rapidly growing range of spatial scales and field intensities. Here we experimentally demonstrate a method to generate intense THz pulses on a metal wire, thereby introducing the possibility of wave-guiding and focussing of the full THz pulse energy to subwavelength spotsizes. This enables endoscopic sensing, single-shot subwavelength THz imaging and study of strongly nonlinear THz phenomena. We generate THz surface plasmon polaritons (SPPs) by launching electron bunches onto the tip of a bare metal wire. Bunches with 160 pC charge and ≈6 ps duration yield SPPs with 6-10 ps duration and 0.4±0.1 MV m^-1 electric field strength on a 1.5 mm diameter aluminium wire. These are the most intense SPPs reported on a wire. The SPPs are shown to propagate around a 90° bend.

中文翻译：

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相对论电子激发的裸金属线上的单周期表面等离激元极化子。

太赫兹（THz）脉冲应用于材料科学，通信和生物传感等各种领域。太赫兹脉冲的亚波长集中技术使人们能够获得迅速增长的空间尺度和场强范围。在这里，我们通过实验证明了一种在金属线上产生强烈太赫兹脉冲的方法，从而引入了将整个太赫兹脉冲能量进行导波和聚焦的可能性，使其达到亚波长斑点。这使得能够进行内窥镜传感，单次亚波长太赫兹成像以及研究强非线性太赫兹现象。我们通过将电子束发射到裸金属线的尖端上来产生太赫兹表面等离子体激元极化子（SPPs）。具有160 pC电荷和≈6ps持续时间的束产生6-10 ps持续时间和0.4±0.1 MV m ^-1的SPP直径1.5毫米的铝线上的电场强度。这些是电线上报告的强度最高的SPP。如图所示，SPP绕90°弯曲传播。