Light-induced radially polarized magnetic fields

Many ferromagnets exhibit the inverse Faraday effect (IFE), and based on the IFE, magnetic fields with different distributions can be induced conveniently in these ferromagnets by tailoring the laser fields. Besides, the magnetic field induced by IFE has been conceived as a far-field and non-invasive method to manipulate the magnetization. Up to now longitudinal magnetic fields, transverse magnetic fields and even a vector magnetic field, where its polarization is along the azimuthal direction, have been generated. However, another vector magnetic field, where its polarization along the radial direction has not been reported yet. In this paper, by focusing two counter-propagating cylindrical vector beams (CVBs) in a 4Pi tightly focusing system, we theoretically tailor the polarization and distribution of the highly confined focused electric field, and a radially polarized magnetic field (RPMF) is generated in the focal plane through the IFE. This RPMF can facilitate the development of the technology of magneto-optical recording. The distribution of induced magnetization in the defocus plane of the 4pi tightly focusing system is also surveyed in this paper.