Polychromatic dynamic localization in curved photonic lattices

Dynamic localization is the suppression of the broadening of a charged-particle wave packet as it moves along a periodic potential in an a.c. electric field ^1-3 . The same effect occurs for optical beams in curved photonic lattices, where the lattice bending has the role of the driving field, and leads to the cancellation of diffraction ^4-8 . Dynamic localization was also observed for Bose-Einstein condensates ⁹ , and could have a role in the spin dynamics of molecular magnets ¹⁰ . It has been predicated that dynamic localization will occur in multidimensional lattices at a series of resonances between lattice, particle and driving-field parameters ¹ . However, only the first dynamic localization resonance in one-dimensional lattices has been observed in any physical system ^6-9 . Here, we report on the experimental observation of higher-order and mixed dynamic localization resonances in both one- and two-dimensional photonic lattices. New features such as spectral broadening of the dynamic localization resonances and localization-induced transformation of the lattice symmetry are demonstrated. These phenomena could be used to shape polychromatic beams emitted by supercontinuum light sources ^11,12 .