Demonstrating more than 2π phase modulation in non-Hermitian asymmetric multilayers

Abstract

Phase modulation has come to be recognized as a fundamental paradigm for optical device design in applications involving the spatiotemporal control of optical wavefronts. Here, the cavities use a combination of absorptive and lossless layers with ideal conductive metal to control reflection and phase shift, similar to the Fabry–Pérot system, which has zero reflection and perfect transmission. Multilayers with different sequences and composed of several stack layers were examined for reflectivity when activated in a prism-coupled layout. The layer’s different arrangements, resulting in open and closed asymmetric multilayers, display reflectance spectra with distinct features as well as phase and shifts. In the open configuration, there is a strong coupling between the hybridized resonance mode and the exciton from the red dye. As a result, energy-based topological considerations identify a correlation between exciton/polariton strong coupling, topological darkness, and phase tuning, and they motivate the 3 π phase shift range.