# Effect of photonic spin-orbit coupling on the topological edge modes of a Su-Schrieffer-Heeger chain

## TL;DR

This paper investigates how photonic spin-orbit coupling influences topological edge states in a one-dimensional zigzag micropillar lattice, revealing a fine structure that enables manipulation of these states.

## Contribution

It introduces the study of SOC effects on topological edge modes in a Su-Schrieffer-Heeger chain with internal degrees of freedom, combining experimental photoluminescence analysis with topological insights.

## Key findings

- SOC causes a fine structure in edge states
- Edge modes penetrate differently into the bulk depending on SOC strength
- Manipulation of topological states via SOC is demonstrated

## Abstract

We study the effect of photonic spin-orbit coupling (SOC) in micropillar lattices on the topological edge states of a one-dimensional chain with a zigzag geometry, corresponding to the Su-Schrieffer-Heeger model equipped with an additional internal degree of freedom. The system combines the strong hopping anisotropy of the $p$-type pillar modes with the large TE-TM splitting in Bragg microcavities. By resolving the photoluminescence emission in energy and polarization we probe the effects of the resulting SOC on the spatial and spectral properties of the edge modes. We find that the edge modes feature a fine structure of states that penetrate by different amounts into the bulk of the chain, depending on the strength of the SOC terms present, thereby opening a route to manipulation of the topological states in the system.