Researchers at the Joint Quantum Institute have made some silicon waveguide resonators that allow light to propagate in just the edge states of the material with low loss when the wavelength of light incident is an integer multiple of the resonators circumference. When the resonators are arranged in an array, light of only the resonant frequency can propagate between resonators. The structures can be used in quantum computing, optical delay lines, optical switches, and optical filters. The system confines light in two dimensions and allows researchers to build hybrid electron-photon-atomic systems.