Phys.org  July 20, 2018 Exceptional points (EP) are singularities in the energy functions of a physical system at which two light modes coalesce to produce unusual effects. Understanding the mechanisms responsible for linewidth broadening will enable laser resources with new capabilities. An international of researchers led by the US used an optomechanical system with two coupled silica whispering-gallery-mode microresonators to exploit the interplay between gain and loss to tune a phonon laser to an EP. The team provided direct experimental evidence to show complete overlap of optical supermodes at EP, and that EP-enhanced optical noise can be transferred directly to […]