Photonic Bloch oscillations and Zener tunneling in two-dimensional   optical lattices
  We report on the first experimental observation of photonic Bloch oscillations and Zener tunneling in two-dimensional periodic systems. We study the propagation of an optical beam in a square photonic lattice superimposed on a refractive index ramp, and demonstrate the tunneling of light from the first to the higher-order transmission bands of the lattice bandgap spectrum, associated with the spectral dynamics inside the first Brillouin zone and corresponding oscillations of the primary beam. 
Henrike Trompeter, Wieslaw Krolikowski, Dragomir N. Neshev, Anton S.   Desyatnikov, Andrey A. Sukhorukov, Yuri S. Kivshar, T...