Open AccessSpherical and sub-wavelength longitudinal magnetization generated by 4π tightly focusing radially polarized vortex beams
Author(s) -
Zhongquan Nie,
Weiqiang Ding,
Dongyu Li,
Xueru Zhang,
Yuxiao Wang,
Song Ye
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.000690
Subject(s) - optics , physics , vortex , numerical aperture , magnetization , faraday effect , optical vortex , beam (structure) , wavelength , light beam , optical tweezers , diffraction , magnetic field , quantum mechanics , thermodynamics
Based on the vector diffraction theory and the inverse Faraday effect, we numerically study the light-induced magnetization near the focus of a 4π high numerical aperture focusing configuration under the illumination of two counter- propagating radially polarized hollow Gaussian vortex beams. The simulated results demonstrate that, by selecting higher-order vortex beam modes (e.g. n=4with n - the beam order) and proper truncation parameter (e.g. β=1.75 with β- the ratio of the pupil radius to the incident beam waist), spherical and sub-wavelength longitudinal magnetization can be generated in the vicinity of focus. Such special magnetization feature is attributed to not only the interaction between optical vortices and the radially polarized beams, but also the completely destructive interference of azimuthal components and the constructive interference of the longitudinal component of the two counter-propagating radially polarized vortex beams. This spherical and sub-wavelength longitudinal magnetization distribution may be of interest for applications in all-optical magnetic recording and confocal and magnetic resonance microscopy.