Revealing Hidden Topology of Complex Vector Beams via Plasmonic Interactions

TL;DR

This paper demonstrates how plasmonic interactions can reveal the hidden topological structures of complex vector beams with space-variant polarization, using tunable liquid crystal devices and nano-structure interactions.

Contribution

It introduces a method to visualize the hidden topology of structured light beams through plasmonic excitation, combining liquid crystal modulation with nano-structure interactions.

Findings

Polarization-dependent excitation of surface plasmons reveals topological features.

Tunable input parameters produce diverse topological patterns.

Observable plasmonic vortices and interference patterns are generated.

Abstract

Structured light beams with space-variant polarization can be efficiently generated using voltage-tunable nematic liquid-crystal (Q-plate). By appropriately selecting the input state and the retardation of the Q-plate, an optical field acquires a spatially structured polarization distribution that is capable of encoding non-trivial topological information across the beam profile. These features can be directly read out through interaction with plasmonic nano-structures, such as circular and spiral slits. Here we show that, upon illumination, polarization-dependent excitation of surface plasmons converts the hidden topology of the polarization structure into observable intensity distributions, including plasmonic vortices and characteristic interference patterns, while the tunability of the input parameters enables a rich variety of distinct topological forms.