Demonstration of an in-phase, coherently-coupled 37-element VECSEL array

Electrically-injected vertical external cavity surface emitting laser (VECSEL) arrays are an attractive source for lowcost, high-brightness applications. Optical pumping can be used to investigate the emission properties of such devices without undergoing complex device fabrication. The design of such arrays is based on a single VECSEL chip, a 2D lens array, and a flat output coupling dichroic mirror. In this work, we report on the demonstration of an optically pumped, coherently-coupled VECSEL array. The array achieves a maximum total output power of >60 mW and lasing spectrum indicates single-mode operation. Near-field characterization reveals 37 individual lasing elements in a hexagonal array. Far-field measurements show an interference pattern which is consistent with inphase coherent coupling, with >60% of the total output power present in the on-axis central lobe. The physical origin of coherent coupling is attributed to diffractive coupling. The simplicity of the optical cavity design suggests scalability to much larger arrays, making the result of particular interest to the development of low-cost, highbrightness diode sources.