GENERATION AND STABILITY OF OPTICAL BULLETS IN QUADRATIC NONLINEAR MEDIA

We show numerically that modulational instability of two-dimensional s olitary waves in quadratic media leads to the formation of a train of quasi-stable three-dimensional light bullets of mutually trapped funda mental and second harmonic pulses. The dynamics and stability of these bullets are studied both numerically and variationally. Small deviati ons fi om the stationary bullet profile generally lead to long lived p ulsations. Regions of unstable behaviour (decay) are found for both po sitive and negative mismatches. (C) 1998 Elsevier Science B.V.