Observation of photonic Landau levels in strained honeycomb lattices

Photonic resonators consisting of semiconductor coupled micropillars arranged in hexagonal lattices (Fig. 1(a)) provide an excellent platform to study, emulate and control the transport and topological properties of single-layered 2D materials like graphene [1]. The lattices of photonic micropillars allow the control of the onsite energies, nearest-neighbours coupling and direct access to the dispersion and wave functions in simple photoluminescence experiments. Even though photons are barely sensitive to magnetic fields, it has been shown that the engineering of a hopping gradient in a honeycomb lattice creates an artificial valley dependent magnetic field [2]. The intensity of this pseudo-magnetic field is directly proportional to the hopping gradient applied to the lattice.