Cylindrically polarized Bessel-Gauss beams

TL;DR

This paper investigates radially and azimuthally polarized Bessel-Gauss beams, analyzing the validity of the paraxial approximation and demonstrating that nonparaxial corrections are negligible across regimes.

Contribution

It provides explicit expressions for nonparaxial vector electric fields and assesses the paraxial approximation's validity for these beams.

Findings

Nonparaxial corrections are negligible regardless of aperture cone angle.

Explicit nonparaxial electric field expressions are derived.

The paraxial approximation remains valid in studied regimes.

Abstract

We present a study of radially and azimuthally polarized Bessel-Gauss beams in both the paraxial and nonparaxial regimes. We discuss the validity of the paraxial approximation and the form of the nonparaxial corrections for Bessel-Gauss beams. We show that, independently from the ratio between the Bessel aperture cone angle $\vartheta_0$ and the Gauss beam divergence $\theta_0$, the nonparaxial corrections are always very small and therefore negligible. Explicit expressions for the nonparaxial vector electric field components are also reported.