Properties of the Poynting vector for invariant beams: negative propagation in Weber beams

TL;DR

This paper derives a general Poynting vector expression for invariant beams with cylindrical symmetry, investigates negative propagation phenomena, and explores implications for optical manipulation, focusing on Weber beams as a case study.

Contribution

It introduces a unified Poynting vector formulation for invariant beams and analyzes negative propagation independently of mode mixing, with specific application to Weber beams.

Findings

Negative propagation can occur independently of mode mixing.

A general Poynting vector expression for invariant beams is proposed.

Implications for micro manipulation and optical forces are discussed.

Abstract

Negative propagation is an uncommon response produced by the local sign change in Poynting vector components. We present a general Poynting vector expression for all invariant beams with cylindrical symmetry using scalar potentials in order to evaluate the possibility of negative propagation. We analyze the plausibility of negative propagation being independent of mode mixing; we study Weber beams as a particular case. The study of this negative effect allow us to advance in the field of micro manipulation and understanding of optical forces. Applications of these beams are discussed.