Tandem light bullets

We put forward a novel strategy to achieve formation of fully three-dimensional light bullets. The new scheme is based on tandem structures where nonlinearity and group-velocity dispersion required for the self-trapping of light are spatially distributed, opening the door for the possibility that they are not necessarily contributed by the same crystal. We show that multicolor light bullets do exist for a variety of tandems with feasible domain lengths. (C) 2001 Elsevier Science B.V. All rights reserved.