Spontaneously implemented spatial coherence in vertical-cavity surface-emitting laser dot array

We report a self-induced spatially-coherent dot array consisting of fourteen units of vertical-cavity surface-emitting modes that exhibit spatially uniform spectra. A 47.5 mu m total beam width and 0.5 degrees narrow emission are achieved using an oblong cavity enclosed with a flat top mirror, cylindrically curved bottom mirror, and side facet. Notably, terminating the side of the cavity with a perpendicular facet enhances the horizontal propagation, which couples with the vertical resonance in each dot, similar to the case of master lasers in injection-locked lasers that delocalize the modes. Conventional semiconductor lasers, edge-emitting lasers, and vertical-cavity surface-emitting lasers have a Fabry-Perot cavity; furthermore, emission and resonance are in identical directions, limiting the beam width to micrometers. Though the present structure has the same scheme of propagation, the right-angled facet synchronizes the modes and drastically expands the beam width.

Automated summary

We present a self-induced spatially-coherent dot array composed of fourteen units of vertical-cavity surface-emitting modes, which exhibit spatially uniform spectra. By employing a specific cavity design and adding a perpendicular facet on the side, we achieve a wide beam width and narrow emission angle.