Composite bound states of spatial optical solitons

This work generalizes the concept of scalar bound states of spatial optical solitons by introducing vector soliton clusters, consisting of incoherent light beams (the components of a vector soliton cluster), each consisting of coherent fundamental solitons. Vector clusters include, as a particular case, previously studied multipole- and necklace-ring vector solitons. Indeed, the well known dipole-mode soliton, or its rotating counterpart, the propeller soliton, though were found as a guided modes of the soliton-induced waveguide, can be presented as a bound state of three solitons: two out-of-phase coherent solitons in one component, whose mutual repulsion is balanced out by the incoherent attraction of the third soliton. Following this approach, different configurations of rotating vector clusters are constructed, consisting of different number of solitons in each component, some of them demonstrating remarkably robust propagation over hundreds of the diffraction lengths. Thus, the vectorial interaction allows the construction of a rich variety of the soliton bound states, and provides the additional azimuthal stabilization of these bound states.