Phys.org November 18, 2019
Optical resonators’ performance is often limited by out-of-plane-scattering losses caused by inevitable fabrication imperfections. An international team of researchers (China, USA – MIT, University of Pennsylvania) proposed and experimentally demonstrated a class of guided resonances in photonic crystal slabs, in which out-of-plane-scattering losses are strongly suppressed by their topological nature. These resonances arise when multiple bound states in the continuum, merge in momentum space and enhance the quality factors Q of all nearby resonances in the same band. Using such resonances in the telecommunication regime, they experimentally achieved quality factor 10 times greater than other devices that don’t use merging topological charges. Their work paves the way for future explorations of topological photonics in systems with open boundary conditions and for their application to the improvement of optoelectronic devices in photonic integrated circuits…read more. TECHNICAL ARTICLEÂ
The separate charges can merge. The wavy landscape along the bottom of the image connects to the periodic nature of the device itself. Credit: Lei Chen