Experimental observation of coherent perfect absorption in anti-parity-time-symmetric side-coupled microwave resonators
Phys. Rev. A 113, 063512 – Published 4 June, 2026
DOI: https://doi.org/10.1103/hx3m-qpdm
Abstract
The anomalies in light scattering associated with singularities are of great importance in both basic physics research and engineering applications. In this work, we focus on the coherent perfect absorption (CPA) singularities in an anti-parity-time (anti-PT) symmetric system and explore the coherent absorption characteristics of the system under various damping conditions. We theoretically and experimentally demonstrated CPA in both anti-PT symmetric phase and anti-PT symmetry broken phase, where dissipation plays a crucial role in the absorption efficiency of the system. Additionally, we theoretically observe pairs of CPA singularities with opposite topological charges, indicating the topological nature of the CPA in the anti-PT symmetric phase. We depict the movement of the zeros of the scattering matrix in the complex-frequency plane and the generation and annihilation processes of topological charges under different dissipative scenarios. Our work offers a promising platform for investigating non-Hermitian physics in open systems and provides valuable insights into the manipulation of electromagnetic waves in photonic systems.
