Reconfigurable Non-Hermitian Topological Photonic Lattice via Reversible Quantum Dot Waveguides.

Non-Hermitian systems extend conventional Hermitian quantum frameworks by incorporating factors like gain and loss, giving rise to novel phenomena such as exceptional points and the non-Hermitian skin effect. Building on these foundations, non-Hermitian topological photonics merges them with topological band theory, enabling unprecedented control of light. The tunability of non-Hermitian parameters allows for on-demand reconfigurable topological devices within a fixed platform, thereby bridging the gap between exotic non-Hermitian topological phenomena and practical applications. Here, we present a reconfigurable non-Hermitian topological photonic lattice with tunable loss, realized on a novel platform of reversible perovskite quantum dot waveguide arrays. By strategically modulating the waveguide loss, we experimentally demonstrate a non-Hermitian-induced topological phase transition and the emergence of interface states. The reversible and tunable characteristics of perovskite quantum dot waveguides establish a versatile platform for exploring topological states and advancing on-chip photonic applications.