Transformation of vector beams with radial and azimuthal polarizations in biaxial crystals

TL;DR

This paper investigates how radially and azimuthally polarized vector beams transform when passing through biaxial crystals, revealing ring-like structures with specific polarization patterns due to conical refraction.

Contribution

It provides both experimental and theoretical analysis of polarization transformations of vector beams in biaxial crystals, highlighting the formation of azimuthal nodes and polarization states.

Findings

Ring-like light structures with azimuthal nodes are formed at the focal plane.

Diametrically opposite points on the ring are linearly orthogonally polarized.

The transformed beams exhibit conical refraction-like polarization states.

Abstract

We present both experimentally and theoretically the transformation of radially and azimuthally polarized vector beams when they propagate through a biaxial crystal and are transformed by the conical refraction phenomenon. We show that, at the focal plane, the transverse pattern is formed by a ring-like light structure with an azimuthal node, being this node found at diametrically opposite points of the ring for radial/azimuthal polarizations. We also prove that the state of polarization of the transformed beams is conical refraction-like, i.e. that every two diametrically opposite points of the light ring are linearly orthogonally polarized.