Generating Sub–Wavelength Longitudinal Magnetization Chains using High NA Lens System

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ABSTRACT

This study investigates the light-induced magnetization distribution produced by a closely focused, azimuthally polarized Laguerre-Bessel-Gaussian beam, which is superimposed with a helical phase and modulated by an optimized multi-belt complex phase filter (MBCPF). Utilizing vector diffraction theory and the inverse Faraday Effect, we numerically analyze the resulting magnetization patterns. Our findings reveal that by adjusting the radii of the complex phase filter’s rings, various novel magnetization focal distributions can be achieved. These include the formation of multiple sub-wavelength spherical magnetization spots arranged in chains of two, three, five, and seven. These configurations are particularly suitable for applications such as transporting multiple magnetic particles, storing multilayer magneto-optical data, developing ultra-compact optomagnetic devices, and fabricating magnetic lattices for spin wave operations.

Significance of the study:

This study presents a novel method to generate sub-wavelength longitudinal magnetization chains using tightly focused, azimuthally polarized Laguerre-Bessel-Gaussian beams and a multi-belt complex phase filter. The ability to create precise magnetization patterns at sub-wavelength scales has significant implications for advanced applications such as multilayer magneto-optical data storage, ultra-compact optomagnetic devices, magnetic particle manipulation, and spin wave operations.

Summary of the study:

The research demonstrates that adjusting the ring radii of a multi-belt complex phase filter allows the formation of novel sub-wavelength magnetization patterns using focused Laguerre-Bessel-Gaussian beams. These patterns include chains of magnetization spots, suitable for applications like magnetic particle transport, multilayer data storage, and optomagnetic devices. The study employs vector diffraction theory and the inverse Faraday Effect, revealing the potential for precise manipulation of magnetization fields.