© The Author(s) 2016. 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.
Op’t Root, W. P. E. M., Brussaard, G. J. H., Smorenburg, P. W., & Luiten, O. J. (2016). Single-cycle surface plasmon polaritons on a bare metal wire excited by relativistic electrons. Nature Communications, 7. https://doi.org/10.1038/ncomms13769