Generation of ultra-long pure magnetization needle and multiple spots by phase modulated doughnut Gaussian beam
Abstract
Based on vector diffraction theory and inverse Faraday effect (IFE), the light induced magnetization distribution of a tightly focused azimuthally polarized doughnut Gaussian beam superimposed with a helical phase and modulated by an optimized multi belt complex phase filter (MBCPF) is analysed numerically. It is noted that by adjusting the radii of different rings of the complex phase filter, one can achieve many novel magnetization focal distribution such as sub wavelength scale (0.29λ) and super long (52.2λ) longitudinal magnetic probe suitable for all optical magnetic recording and the formation of multiple magnetization chain with four, six and eight sub-wavelength spherical magnetization spots suitable for multiple trapping of magnetic particles are achieved.
- Publication:
-
Optics Laser Technology
- Pub Date:
- June 2018
- DOI:
- 10.1016/j.optlastec.2017.12.008
- Bibcode:
- 2018OptLT.102...40U
- Keywords:
-
- Vector diffraction theory;
- Inverse Faraday effect;
- Doughnut Gaussian beam;
- Multiple optical trapping;
- High NA lens