Observation of a Localized Flat-Band State in a Photonic Lieb Lattice

We demonstrate the first experimental realization of a dispersionless state, in a photonic Lieb lattice formed by an array of optical waveguides. This engineered lattice supports three energy bands, including a perfectly flat middle band with an infinite effective mass. We analyze, both experimentally and theoretically, the evolution of well-prepared flat-band states, and show their remarkable robustness, even in the presence of disorder. The realization of flat-band states in photonic lattices opens an exciting door towards quantum simulation of flat-band models in a highly controllable environment.

• DF
  Deutsche Forschungsgemeinschaft

  Award: 462/6-1
• EA
  Engineering and Physical Sciences Research Council

  Award: EP/M024636/1
• SA
  Science and Technology Facilities Council

  Awards: ST/H005595/1, ST/K00235X/1, ST/K00235X/1, ST/H005595/1