Experimental verification of a plasmonic hook in a dielectric Janus particle

Abstract

We report on the experimental observation of the curved plasmonic beam, a plasmonic hook (PH), for surface plasmon-polariton (SPP) waves. The SPP PH effect could be obtained with a cuboid particle with broken shape symmetry fabricated with a relatively simple routine. This has a pronounced difference with fabrication of the structure for generation of the Airy SPPs, which require complex techniques to compensate the wave vector mismatch. We confirmed the existence of SPP PH by amplitude scattering scanning near-field optical microscopy. The experimental results agree well with our predictions. Importantly, the SPP PH demonstrates the smallest curvature of the beam ever recorded for SPPs compared to that for the Airy-family plasmonic beams, which potentially can strongly impact many useful applications from nanoparticle manipulation to nanoscale bio-sensing.