# Multi-twist polarization ribbon topologies in highly-confined optical fields

## TL;DR

This paper demonstrates that tightly focused structured optical beams can produce complex 3D polarization topologies, specifically a double-twisted ribbon, revealing new insights into light's behavior under extreme focusing conditions.

## Contribution

It introduces the experimental observation of a multi-twist polarization ribbon topology in highly-confined optical fields, expanding understanding of light's complex polarization structures.

## Key findings

- Observation of a double-twisted polarization ribbon in the focal volume
- Experimental analysis of the ribbon's stability and dynamics
- Dependence of topology on focusing parameters and propagation planes

## Abstract

Electromagnetic plane waves, solutions to Maxwell's equations, are said to be `transverse' in vacuum. Namely, the waves' oscillatory electric and magnetic fields are confined within a plane transverse to the waves' propagation direction. Under tight-focusing conditions however, the field can exhibit longitudinal electric or magnetic components, transverse spin angular momentum, or non-trivial topologies such as M\"obius strips. Here, we show that when a suitably spatially structured beam is tightly focused, a 3-dimensional polarization topology in the form of a ribbon with two full twists appears in the focal volume. We study experimentally the stability and dynamics of the observed polarization ribbon by exploring its topological structure for various radii upon focusing and for different propagation planes.