Researchers create better light-trapping devices  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 […]