title: Bethe-hole polarization analyser for the magnetic vector of light.
abstract: The nature of light as an electromagnetic wave with transverse components has been confirmed using optical polarizers, which are sensitive to the orientation of the electric field. Recent advances in nanoscale optical technologies demand their magnetic counterpart, which can sense the orientation of the optical magnetic field. Here we report that subwavelength metallic apertures on infinite plane predominantly sense the magnetic field of light, establishing the orientation of the magnetic component of light as a separate entity from its electric counterpart. A subwavelength aperture combined with a tapered optical fibre probe can also serve as a nanoscale polarization analyser for the optical magnetic field, analogous to a nanoparticle sensing the local electric polarization. As proof of its functionality, we demonstrate the measurement of a magnetic field orientation that is parallel to the electric field, as well as a circularly polarized magnetic field in the presence of a linearly polarized electric field.
authors.affiliation: Department of Physics and Astronomy, Center for Subwavelength Optics, Seoul National University, Seoul 151-747, Korea.
authors.forename: H W
authors.initials: HW
authors.lastname: Kihm
authors.forename: S M
authors.initials: SM
authors.lastname: Koo
authors.forename: Q H
authors.initials: QH
authors.lastname: Kim
authors.forename: K
authors.initials: K
authors.lastname: Bao
authors.forename: J E
authors.initials: JE
authors.lastname: Kihm
authors.forename: W S
authors.initials: WS
authors.lastname: Bak
authors.forename: S H
authors.initials: SH
authors.lastname: Eah
authors.forename: C
authors.initials: C
authors.lastname: Lienau
authors.forename: H
authors.initials: H
authors.lastname: Kim
authors.forename: P
authors.initials: P
authors.lastname: Nordlander
authors.forename: N J
authors.initials: NJ
authors.lastname: Halas
authors.forename: N K
authors.initials: NK
authors.lastname: Park
authors.forename: D-S
authors.initials: DS
authors.lastname: Kim