Incomplete Brillouin-zone spectra and controlled Bragg reflection with ionic-type photonic lattices

We demonstrate ionic-type photonic lattices consisting of alternating positive and negative lattice potentials akin to those of ionic crystals in solids. A modified geometrical structure factor is developed for describing Bragg scattering in these non-Bravais photonic lattices. We show that lattice reconfiguration leads to incomplete Brillouin zone spectra due to selective band-gap closures. Experimentally, incomplete Brillouin zone spectra and associated Bragg-reflection suppression are observed in such ionic-type lattices optically induced in a bulk nonlinear crystal. Our experimental results agree well with our theoretical analysis.