Polarization structure of a Bessel–Gaussian beam in a gyroanisotropic medium

The work shows that a Bessel–Gaussian beam propagating through a gyroanisotropic optically active medium forms a polarization pattern of eigenmodes for non-diffracting beams and is a superposition of TE and TM modes with corresponding amplitude coefficients. It is shown that a medium with pure optical activity allows for mutual conversion of beams with radial and azimuthal polarization distributions. It is shown that in a Bessel beam with an initial linear polarization, a cross-like conoscopic pattern is observed in the orthogonal component, formed by an array of optical vortices. The evolution of the polarization state distribution and the transformation of spin angular momentum in a low-order Bessel beam propagating in a saturated sugar solution are considered.