# Tunable Skyrmion, Meron, and Skyrmion Bag Textures in Surface Phonon Polariton Lattices

## TL;DR

This paper introduces a tunable platform for creating and controlling topological light textures using surface phonon polaritons on silicon carbide membranes.

## Contribution

The study proposes a dynamically tunable platform for generating diverse topological textures with controllable field confinement and spin properties.

## Key findings

- Tunable transitions between bubble-type and Néel-type topological textures are demonstrated via wavelength control.
- A novel singularity-type meron is identified with conserved topological charge and spatially confined spin reversal.

## Abstract

Surface phonon polaritons (SPhPs) enable nanoscale manipulation of mid‐infrared light via deeply subwavelength topological vector textures, such as skyrmions. Achieving dynamic, real‐time control over these topological features remains challenging. Here, we theoretically propose and numerically demonstrate an actively tunable platform on a silicon carbide membrane that creates lattices of diverse topological textures, including skyrmions, merons, and skyrmion bags. By exploiting the sublinear SPhP dispersion, we dynamically adjust the excitation wavelength to tune the topological character of these lattices. This enables tunability between bubble‐type and Néel‐type configurations, controlling field confinement and topology for topological textures in the electric field and the spin angular momentum. Furthermore, we identify a novel singularity‐type meron arising from the interplay of electric and magnetic spin components. This texture exhibits topological charge conservation in moiré superlattices and a spatially confined spin reversal with tunable lateral sizes as low as λSPhP/29 and skyrmion number density confinements as low as λSPhP/64. These findings provide a versatile framework for on‐chip, reconfigurable topological photonic devices with potential applications in high‐resolution imaging and precision metrology in the mid‐infrared. The results can be readily extended to other topological systems, where similar dispersion relations hold.

We present surface phonon polariton skyrmions, merons, and skyrmion bags on SiC membranes and study the influence on their topology when tuning the excitation wavelength. We present simulation results on the bubble‐to‐Néel‐type transition of the topological textures in the electric field and spin angular momentum and study singularity‐type electric field spin merons and their topological charge conservation in moiré lattices.