2017/03/07 by Denis Garoli, Garoli, Denis, Pierfrancesco Zilio +5
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Metamaterials and Metasurfaces Applications #Optics (physics.optics) #Orbital Angular Momentum in Optics #Plasmonic and Surface Plasmon Research
paper · pdf · doi:10.48550/arxiv.1703.02278
openalex publication_date 2017/03/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Surface plasmon waves carry an intrinsic transverse spin, which is locked to its propagation direction. Apparently, when a singular plasmonic mode is guided on a conic surface this spin-locking may lead to a strong circular polarization of the far-field emission. Specifically, an adiabatically tapered gold nanocone guides an a priori excited plasmonic vortex upwards where the mode accelerates and finally beams out from the tip apex. The helicity of this beam is shown to be single-handed and stems solely from the transverse spin-locking of the helical plasmonic wave-front. We present a simple geometric model that fully predicts the emerging light spin in our system. Finally we experimentally demonstrate the helicity-locking phenomenon by using accurately fabricated nanostructures and confirm the results with the model and numerical data.