Phase-dependent interactions between three-wave spatial solitons in bulk quadratic media

We report the first experimental observation, to our knowledge, of phase-controlled three-wave interactions between two spatial solitons in a bulk quadratic nonlinear crystal. We demonstrate that the nature of the interaction can be attractive or repulsive, depending on the phase relationships between the input beams at the fundamental frequency and their power imbalance. Full control of the interaction is achieved by the adjustment of the relative phases and/or the orientation of the input waves, leading to scattering, fusion, spiraling, and power-exchange phenomena. Experimental observations are in good qualitative agreement with the corresponding theoretical and numerical results. (C) 2003 Optical Society of America.