Two-color discrete localized modes and resonant scattering in arrays of   nonlinear quadratic optical waveguides
  We analyze the properties and stability of two-color discrete localized modes in arrays of channel waveguides where tunable quadratic nonlinearity is introduced as a nonlinear defect by periodic poling of a single waveguide in the array. We show that, depending on the value of the phase mismatch and the input power, such two-color defect modes can be realized in three different localized states. We also study resonant light scattering in the arrays with the defect waveguide. 
M. I. Molina, R. A. Vicencio and Y. S. Kivshar