We investigate light localization at a single phase-slip defect in one-dimensional photonic lattices, both numerically and experimentally. We demonstrate the existence of various robust linear and nonlinear localized modes in lithium niobate waveguide arrays exhibiting saturable defocusing nonlinearity.

We consider, both experimentally and theoretically, the existence and stability of localized, symmetric, and antisymmetric gap solitons (GSs) in binary lattices of identical waveguides but with alternating spacings. Furthermore, the properties of surface GSs at the boundary of the lattice are explored.

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Ni-Zn ferrites, with the general formula Ni 1-x Zn x Fe 2 O 4 (x = 0.0, 0.3, 0.5, 0.7, 1.0), CoFe 2 O 4 , BaTiO 3 and PbZr 0.52 Ti 0.48 O 3 powders were synthesized by auto-combustion method. The composites were prepared by mixing the appropriate amounts of individual phases, pressing and conventional sintering. X-ray analysis, for individual phase and composites, indicated the formation of crystallized structure of NiZnFe 2 O 4 , BaTiO 3 and PbZr 0.52 Ti 0.48 O 3 without the presence of secondary phases or any impurities. SEM analyses indicated a formation of uniform grain distribution for ferromagnetic and ferroelectric phases and formation of two types of grains, polygonal and rounded, respectively. Magneto-dielectric effect was exhibited in all samples because of the applied stress occurring due to the piezomagnetic effect and the magnetic field induced the variation of the dielectric constant. For all samples the dielectric constant was higher in applied magnetic field. At the low frequency, the dispersion of dielectric losses appeared, while at the higher frequency the value of tan δ become constant (Maxwell-Wagner relaxation). Investigation of J-E relation between leakage and electric field revealed that both nickel zinc ferrite and composites have three different regions of conduction: region with ohmic conduction mechanism, region with the trap-controlled space charge limited current mechanism and region with space charge limited current mechanism.

We investigate linear and nonlinear light propagation at the interface of two one-dimensional homogeneous waveguide arrays containing a single defect of different strength. For the linear case and in a limited region of the defect size, we find trapped staggered and unstaggered modes. In the nonlinear case, we study the dependence of power thresholds for discrete soliton formation in different channels as a function of defect strength. All experimental results are confirmed theoretically using an adequate discrete model.