Shaping and control of polychromatic light in nonlinear photonic lattices

We overview our recent results on spatio-spectral control, diffraction management, broadband switching, and self-trapping of polychromatic light in periodic photonic lattices in the form of rainbow gap solitons, polychromatic surface waves, and multigap color breathers. We show that an interplay of wave scattering from a periodic structure and interaction of multiple colors in media with slow nonlinear response can be used to selectively separate or combine different spectral components. We use an array of optical waveguides fabricated in a LiNbO₃ crystal to actively control the output spectrum of the supercontinuum radiation and generate polychromatic gap solitons through a sharp transition from spatial separation of spectral components to the simultaneous spatio-spectral localization of supercontinuum light. We also show that by introducing specially optimized periodic bending of waveguides in the longitudinal direction, one can manage the strength and type of diffraction in an ultra-broad spectral region and, in particular, realize the multicolor Talbot effect.