title: Corrugation-assisted metal-coated angled fiber facet for wavelength-dependent off-axis directional beaming.
abstract: We propose a fiber-optic-plasmonic hybrid device that is based on a corrugation-assisted metal-coated angled fiber facet (CA-MCAFF) for wavelength-dependent off-axis directional beaming (WODB). The device breaks into two key structures: One is the MCAFF structure, which is a modified Kretschmann configuration implemented onto a fiber platform, thereby being able to generate a unidirectional surface plasmon with dramatically enhanced properties in terms of non-confined diffracted radiation loss and operational bandwidth. The other is the periodic corrugation structure put on the MCAFF, thereby enabling WODB functionality out of the whole structures. The corrugated metal surface out-couples the surface plasmon mode to free-space optical radiation into a direction that varies with the wavelength of the optical radiation with excellent linearity. We perform extensive numerical investigations based on the finite-element-method and analyze the out-coupling efficiency (OCEout) and spectral bandwidth (SBout) of the proposed device for various designs and conditions. We determine the seven structural parameters of the device via taking sequential optimization steps. We deduce two optimal conditions particularly for the fiber-facet angle, in terms of the averaged OCEoutor the SBoutin the whole visible wavelength range (400 - 700 nm), which eventually leads to OCEout= 30.4% and SBout= 230 nm or to OCEout= 24.5% and SBout= 245 nm, respectively. These results suggest substantial enhancements in both OCEoutand SBout, in comparison with the performance properties of a typical nano-slit-based device having a similar type of WODB functionality. The proposed CA-MCAFF is a simple, compact and efficient WODB device that is fully compatible with the state-of-the-art optical fiber technology.
authors.forename: Hyuntai
authors.initials: H
authors.lastname: Kim
authors.forename: Haechan
authors.initials: H
authors.lastname: An
authors.forename: Jinseob
authors.initials: J
authors.lastname: Kim
authors.forename: Seungsu
authors.initials: S
authors.lastname: Lee
authors.forename: Kyoungyoon
authors.initials: K
authors.lastname: Park
authors.forename: Seungjong
authors.initials: S
authors.lastname: Lee
authors.forename: Seungsoo
authors.initials: S
authors.lastname: Hong
authors.forename: Luis Alonso
authors.initials: LA
authors.lastname: Vazquez-Zuniga
authors.forename: Seung-Yeol
authors.initials: SY
authors.lastname: Lee
authors.forename: Byoungho
authors.initials: B
authors.lastname: Lee
authors.forename: Yoonchan
authors.initials: Y
authors.lastname: Jeong