Generation of quadratic spatially trapped beams with short pulsed light

We report a numerical and experimental investigation on the generation of spatial self-narrowed beams with short temporal pulsed excitation in quadratic film waveguides. The impact of temporal group-velocity mismatch between the quadratic multiple interacting signals is shown. We accurately studied the spatial, temporal and spectral signals dynamics versus pulse power and phase mismatch. We show that spatial self-trapping can be induced even if the pump pulse duration is significantly shorter than the group delay mismatch between interacting waves for large enough positive phase mismatches.