Open AccessPlasmonic Archimedean spiral modes on concentric metal ring gratings
Author(s) -
YiTing Lai,
Bingying Cheng,
Yung Chiang Lan,
Din Ping Tsai
Publication year - 2016
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.015021
Subject(s) - grating , plasmon , nanorod , optics , spiral (railway) , surface plasmon , physics , surface plasmon polariton , angular momentum , ring (chemistry) , materials science , nanotechnology , chemistry , classical mechanics , mathematical analysis , mathematics , organic chemistry
Plasmonic Archimedean spiral modes on concentric silver (Ag) ring gratings are investigated by FDTD simulations and theoretical analyses. These modes are generated by placing the ring grating under an Ag nanorod to extract the orbital angular momentum (OAM) of spiral surface plasmon (SSP) modes on the nanorod and transform it into the orbital motion of SP on the grating. The formation of Archimedean spiral patterns is ascribed to two factors: both the r- and θ-directional wavevectors are conserved for SSP on nanorod coupling into SP on ring grating and both the r- and θ-directional velocities of SP keep unchanged when it propagates on the ring grating. The number of strands of Archimedean spiral pattern is determined by the topological charge of SSP mode. The plasmonic Archimedean spiral modes have potential applications in the fields of data storage, dielectric microparticle manipulation, biosensing and directional switching.