A new nanophotonic resonator efficiently traps light by exploiting a quantum phenomenon called bound states in the continuum (BIC). Researchers at the University of California, San Diego, said the metamaterial cavity could enable optical computing circuits and switches, as well as biosensors and compact solar cells. The device marks the first time BIC has been observed in metamaterials, and contains even smaller cavities than photonic crystals, said professor Dr. Boubacar Kante. Professor Dr. Boubacar Kante, left, and postdoctoral researcher Thomas Lepetit have used a phenomenon called bound states in the continuum to trap light inside a metamaterial resonator. Courtesy of the UC San Diego Jacobs School of Engineering. Most current nanocavities have relatively low quality factors, meaning there are multiple ways for photons to escape them. The new nanocavity, rather than trying limit the size and number of passages where light can escape, approaches the problem from a different angle. It consists of a rectangular metal waveguide and ceramic light scatterer that produce destructive interferences for the light waves inside. Light is allowed to escape, but the multiple waves that do so end up cancelling each other out. Multiple bound states can exist in the system, which makes the light trap more robust and less vulnerable to outside disruptions than other cavities to date. The research was funded in part by a grant from the Qualcomm Institute at UC San Diego. The findings were published in Physical Review B (doi: 10.1103/PhysRevB.90.241103). For more information, visit www.ucsd.edu.