Parity-time symmetric metamaterial for photonics

The paper studies the spectral properties of Parity-Time (PT) symmetric photonic structures based on circular microresonators. A semi-analytical model based on solving the Boundary Integral Equation (BIE) is used to model coupled resonators satisfying the PT-symmetric condition. Unique properties such as asymmetric transmission and a localised defect state are observed. A potential benefit of these properties is the generation of a single frequency laser source for spectroscopy or telecommunication applications.