title: Single-cycle surface plasmon polaritons on a bare metal wire excited by relativistic electrons.
abstract: 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-1electric 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.
authors.affiliation: Coherence and Quantum Technology, Department of Physics, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands.
authors.forename: W P E M
authors.initials: WP
authors.lastname: Op 't Root
authors.affiliation: Coherence and Quantum Technology, Department of Physics, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands.
authors.forename: G J H
authors.initials: GJ
authors.lastname: Brussaard
authors.affiliation: Coherence and Quantum Technology, Department of Physics, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands.
authors.forename: P W
authors.initials: PW
authors.lastname: Smorenburg
authors.affiliation: Coherence and Quantum Technology, Department of Physics, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands.|Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands.
authors.forename: O J
authors.initials: OJ
authors.lastname: Luiten