Polarization description of light fields in terms of meridional and azimuthal vectorial features

In terms of the radial, azimuthal and longitudinal components of the field, the polarization features of 3D electromagnetic beams are described by defining three local parameters, namely, the so-called 3D degree of meridional polarization, the ratio between meridional and azimuthal contributions and the degree of cross-correlation between meridional and azimuthal field components. At each point Q, the term “meridional” refers to the projection of the electric field vector onto a plane containing the point Q and the longitudinal axis z. These parameters are valid for both paraxial and non-paraxial regimes. Accordingly, they can be used for describing highly-focused fields. The analytical relation among the well-known 3D electromagnetic degree of polarization and the above parameters is also obtained, and several simple cases are considered.

► New local parameters have been defined. ► The proposed parameters apply to 3D non-paraxial light fields. ► The parameters describe meridional and azimuthal polarization features. ► The parameters are specially adapted to studying nearly radial and azimuthal fields. ► Relation between the 3D electromagnetic degree of polarization and the new parameters is found.