Simultaneous creation of multiple vortex-antivortex pairs in momentum space in photonic lattices

TL;DR

This paper demonstrates an experimental method to generate multiple vortex-antivortex pairs in momentum space within photonic lattices, revealing how symmetry influences vortex patterns and enabling efficient vortex creation with unstructured light.

Contribution

It introduces a novel experimental approach to create and analyze multiple vortex-antivortex pairs in photonic lattices, highlighting the role of symmetry over topology in vortex pattern formation.

Findings

Vortex arrays are created in momentum space using a single Gaussian beam.

Vortex patterns are influenced by wave packet symmetry, not lattice topology.

The method provides an efficient way to generate multiple vortices in photonic systems.

Abstract

Engineering of the orbital angular momentum (OAM) of light due to interaction with photonic lattices reveals rich physics and motivates potential applications. We report the experimental creation of regularly-distributed quantized vortex arrays in momentum space by probing the honeycomb and hexagonal photonic lattices with a single focused Gaussian beam. For the honeycomb lattice, the vortices are associated with Dirac points and mimic the Berry curvature sources. However, we show that the resulting spatial patterns of vortices are strongly defined by the symmetry of the wave packet evolving in the optical lattice but not by lattice topological properties. Our findings reveal the underlying physics by connecting the symmetry and OAM conversion, and provide a simple and efficient method to create regularly-distributed multiple vortices by unstructured light.