Spatial mode structure of bottom-emitting broad-area vertical-cavity surface-emitting lasers

Abstract

The spatial mode structure of circular broad-area bottom-emitting vertical-cavity surface-emitting lasers is investigated close to threshold. The devices display very high-order flower-like Laguerre modes as well as structures with a Cartesian symmetry in spite of the original O(2) symmetry. In some cases the latter resemble tilted waves more than Hermite-Gaussian modes. Spatial structures appear for both sides of the detuning between the gain peak and the cavity resonance. The results indicate the necessity to refine the theoretical models to include realistic boundary conditions and inhomogeneities.