No abstract

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)

We report on the first experimental observation of dynamic localization of light in two-dimensional photonic lattices. We demonstrate suppression of beam diffraction in hexagonal lattices created by weakly coupled waveguides with axis bending. We also reveal that this effect is strongly related to dynamic localization in zigzag waveguide arrays with next-nearest neighboring interactions.

We predict that interfaces of periodically curved waveguide arrays can support a novel type of surface states which exist in a certain region of modulation parameters associated with the band flattening. Such linear surface states appear in truncated but otherwise perfect (defect-free) lattices as a direct consequence of the periodic modulation of the lattice potential. We show that the existence of these modes in different band gaps can be flexibly controlled by selecting the modulation profile, with no restrictions on Bloch-wave symmetries characteristic of Shockley states.