Frequency generation and solitonic decay in three-wave nonlinear interactions

Three-wave resonant interaction (TWRI) is a universal model that recurs in various branches of science, such as plasma physics, optics, fluid dynamics and acoustics, as it describes the mixing of waves with different frequencies in weakly nonlinear and dispersive media. Here we investigate the TWRI dynamics of two input wave packets at fundamental frequencies which mix to generate a field at the sum frequency. Depending on the input intensities, three different regimes exist. Linear regime: the wave packets at fundamental frequencies don't interact. Frequency conversion: the wave packets at the fundamental frequencies interact and generate a field at the sum frequency. Solitonic regime: the wave packets at the fundamental frequencies interact and generate a field at the sum frequency that sustains a TWRI soliton, which eventually decays into solitons at the fundamental frequencies and radiation. Here we report the experimental evidence of the transition from steady sum frequency generation to solitonic decay in optics. To our knowledge, this is the first experimental observation of TWRI soliton dynamics.