Observation of vortex soliton states in vertical-cavity surface-emitting lasers with feedback

We report on the formation of ring-shaped localized structures in addition to known spatial laser cavity solitons (LCS) in a broad-area vertical-cavity surface-emitting laser (VCSEL) with frequency-selective feedback, for which is providing the minimal model. As the injection current is increased, different scenarios are observed in which the LCS evolve from the fundamental soliton via multi-lobed and ring structures containing phase singularities to more complex patterns. We discuss their bistability and phase locking between a vortex and a fundamental soliton and between two vortices.