Achievement and steering of light-induced sub-wavelength longitudinal magnetization chain

作者:Nie Zhongquan; Ding Weiqiang; Shi Guang; Li Dongyu; Zhang Xueru; Wang Yuxiao; Song Yinglin
来源:Optics Express, 2015, 23(16): 21296-21305.
DOI:10.1364/OE.23.021296

摘要

The light-induced magnetization distributions for a high numerical aperture focusing configuration with an azimuthally polarized Bessel-Gaussian beam modulated by optimized vortex binary filters are investigated based on the inverse Faraday effect. It is found that, by adjusting the radii of different rings of the single/cascaded vortex binary filters, super-long (12 lambda) and sub-wavelength (0.416 lambda) longitudinal magnetization chain with single/dual channels can be achieved in the focal region. Such well-behaved magnetization trait is attributed to the mutual effect between the optical polarization singularities of the azimuthally polarized beam and single/cascaded spiral optical elements. In addition, we find that the displacement distance of the longitudinal magnetization chain is proportional to the phase difference between the inner circle and outer ring of the vortex binary filters, thus giving rise to the steerable magnetization chain. It is expected that the research outcomes can be applied in multiple atoms trapping and transport, multilayer magneto-optical data storage, fabrication of magnetic lattices for spin wave operation and development of ultra-compact optomagnetic devices.