Nonlinear Airy beam propagation in defected photonic lattices

This work theoretically investigates the interplay of nonlinear Airy beams (AB) propagation and optically induced waveguide arrays in a photorefractive (PR) crystal. By introducing defect guides within the photonic lattice, we control the trajectory and self-bending properties and mostly the complex photoinduced waveguiding structures of these unconventional beams. Positive defects within the lattice induce the formation of solitary-like waves, while negative defects result in strong repulsion effects. In the nonlinear regime, these phenomena are further enhanced, with higher solitonic wave intensity in the case of a positive defect. Our simulations further demonstrate that at a lattice period of 20 µm, a specific defect guide modulation depth, and proper nonlinearity strength, a single laser beam injected in a negatively defected waveguide splits into up to seven distinct output channels. By judiciously adjusting the parameters, we can generate output channels that are spatially separated by up to 19 times the beam waist, thereby offering precise control over both the position and intensity of the output channels.