title: Highly efficient singular surface plasmon generation by achiral apertures.
abstract: We report a highly efficient generation of singular surface plasmon (SP) fields by an achiral plasmonic structure consisting of Λ-shaped apertures. Our quantitative analysis, based on leakage radiation microscopy (LRM), demonstrates that the induced spin-orbit coupling can be tuned by adjusting the apex angle of the Λ-shaped aperture. Specifically, the array of Λ-shaped apertures with the apex angle 60° is shown to give rise to the directional coupling efficiency. The ring of Λ-shaped apertures with the apex angle 60° was found to generate the maximum extinction ratio (ER=11) for the SP singularities between two different polarization states. This result provides a more efficient way for developing an SP focusing and an SP vortex in the field of nanophotonics such as optical tweezers.
authors.forename: Quanbo
authors.initials: Q
authors.lastname: Jiang
authors.forename: Aline
authors.initials: A
authors.lastname: Pham
authors.forename: Serge
authors.initials: S
authors.lastname: Huant
authors.forename: Joel
authors.initials: J
authors.lastname: Bellessa
authors.forename: Cyriaque
authors.initials: C
authors.lastname: Genet
authors.forename: Aurélien
authors.initials: A
authors.lastname: Drezet