Macroscopic Zeno Effect in a Su–Schrieffer–Heeger Photonic Topological Insulator

The quantum Zeno effect refers to the slowdown of the decay of a quantum system due to frequent measurements. It has been extended beyond quantum systems, manifesting itself in such phenomena as the suppression of output beam decay by sufficiently strong absorption introduced in guiding optical systems. In this case, the phenomenon is termed as macroscopic Zeno effect. Here the observation of the macroscopic Zeno effect in a topological photonic system is reported. The phenomenon is based on the suppression of decay for only a subspace of edge modes that can propagate in the system and does not rely on the existence of exceptional points. By introducing controlled losses in one of the arms of a topological insulator comprising two closely positioned Su–Schrieffer–Heeger arrays, the macroscopic Zeno effect is demonstrated, which manifests itself in an increase of the transparency of the system with respect to the topological modes created at the interface between two arrays. The phenomenon remains robust against disorder in the non-Hermitian topological regime. In contrast, coupling a topological array with a non-topological one results in a monotonic decrease in output power with increasing absorption.