Reconfigurable and robust topological edge states in photonic crystals

We present a geometrically reconfigurable photonic crystal platform that sustains robust topological edge transport under large radial perturbations. The system is based on a hexagonal dielectric lattice composed of Ta₂O₅ pillars, where a sublattice-selective radius modulation induces a controlled transition between trivial and nontrivial Γ-point topological phases through Mie-resonance p-d band inversion. By systematically varying the pillar radii, we demonstrate that the topological edge states remain stable over a broad perturbation range of up to ±6%. Full-wave simulations confirm robust edge localization and waveguiding across complex geometries. The proposed approach establishes radial geometry reconfiguration as an effective strategy for realizing perturbation-invariant topological photonic waveguides, offering a practical route toward fabrication-tolerant and reconfigurable photonic integrated devices.