Collisional dynamics of vortices in light condensates.

Through numerical simulation, we have studied the nucleation and annihilation of two-dimensional optical vortex solitons hosted in finite size light beams. Our study covers a wide range of angular momentum l> or =1, also referred to as its topological charge. We demonstrate that surface tension of light beams prevents beam filamentation for a certain range of total reflection angles even if the hosted hole splits and decays into several vortices with lower values of l. We also discuss a mechanism for vortex nucleation starting from Gaussian beams that can be used for experimental purposes. Our work adds extra support to the idea that light beams in cubic-quintic nonlinear materials can undergo a phase transition from a photon gas to a liquid of light.