title: Three-dimensional nanoscale far-field focusing of radially polarized light by scattering the SPPs with an annular groove.
abstract: Three-dimensional (3D) nanoscale focusing of radially polarized light in far field by a simple plasmonic lens composed of an annular slit and a single concentric groove is reported. The numerical calculations reveal that the incident light is coupled to surface plasmon polaritons (SPP) by the annular slit and a focal spot with a size less than a half of the illumination wavelength is formed in the far field due to the constructive interference of the scattered light by the groove. More importantly, the focal length can be modulated by changing the groove diameter. This structure provides an admirable choice for the nano-optical devices.
authors.affiliation: State Key Laboratory of Optical Technologies for Microfabrication, Institute of Optics and Electronics, Chinese Academy of Sciences, P. O. Box 350, Chengdu 610209, China.
authors.forename: Maoguo
authors.initials: M
authors.lastname: Zhang
authors.forename: Jinglei
authors.initials: J
authors.lastname: Du
authors.forename: Haofei
authors.initials: H
authors.lastname: Shi
authors.forename: Shaoyun
authors.initials: S
authors.lastname: Yin
authors.forename: Liangping
authors.initials: L
authors.lastname: Xia
authors.forename: Baohua
authors.initials: B
authors.lastname: Jia
authors.forename: Min
authors.initials: M
authors.lastname: Gu
authors.forename: Chunlei
authors.initials: C
authors.lastname: Du