Résumé:

The broad-area vertical-cavity surface-emitting lasers (VCSELs) can be brought into a bistable regime by the use of a frequency-selective feedback (as well as saturable absorbers), leading to the formation of cavity solitons (CSs). Such CSs are generated under electrical injection below the lasing threshold of the VCSEL, and appear in the broad area laser as bright spots. They can also be arranged into self-organized arrays, switched on and off with an external laser holding beam, and brought to high-order states [1]. The self-localization can even be obtained in space and time, and self-pulsing spatial solitons have been demonstrated in a mode-locked VCSEL [2]. Here we explore the topological properties of the high-order states of the CS, and we report the spontaneous formation of anti-vortex CSs with a hyperbolic polarization structure. Beams with a spatially non-uniform distribution of polarization are interesting due to their intrinsic beauty, novel functionalities in quantum optics and newly enabled applications [3]. They possess a circular symmetric intensity structure, most often in form of a doughnut, combined with a spatially non-uniform polarization field containing polarization singularities and are referred to as `vector vortex beams'. The engineering of such vectorial vortex beams has been demonstrated in solid-state lasers with a mesa or a meta-surface shaping the spatial pattern [4], whereas they are here spontaneously obtained in the broad-area laser. Vortex beams, including the exotic anti-vortex reported here, have been predicted within the framework of spin-flip models of VCSELs [5], and result from the interplay between the natural anisotropies of the laser and the spin-dependent gain dynamics.