Reflection of quadratic solitons at the boundary of nonlinear media

We report experimental evidence of soliton reflection at the boundary of quadratic nonlinear media. The evolution of beams incident upon the interface of periodically poled LiNbO3 and uniform LiNbO3 is considered; in the whole device the linear refractive index is homogeneous. Linear beam transmission and soliton reflection at the nonlinear phase-mismatched boundary were observed. Numerical simulations that correspond to the experiments are also presented.