Revealing the subfemtosecond dynamics of orbital angular momentum in nanoplasmonic vortices

• Autores: G. Spektor, D. Kilbane
• Localización: Science, ISSN 0036-8075, Vol. 355, Nº 6330, 2017, págs. 1187-1191
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • The ability of light to carry and deliver orbital angular momentum (OAM) in the form of optical vortices has attracted much interest. The physical properties of light with a helical wavefront can be confined onto two-dimensional surfaces with subwavelength dimensions in the form of plasmonic vortices, opening avenues for thus far unknown light-matter interactions. Because of their extreme rotational velocity, the ultrafast dynamics of such vortices remained unexplored. Here we show the detailed spatiotemporal evolution of nanovortices using time-resolved two-photon photoemission electron microscopy. We observe both long- and short-range plasmonic vortices confined to deep subwavelength dimensions on the scale of 100 nanometers with nanometer spatial resolution and subfemtosecond time-step resolution. Finally, by measuring the angular velocity of the vortex, we directly extract the OAM magnitude of light.