Monolithic integration of vertical-cavity surface-emitting laser and diffractive optical element for advanced beam shaping

We have demonstrated a vertical-cavity surface-emitting laser (VCSEL) with a monolithically integrated diffractive optical element (DOE) for advanced beam shaping. The DOE is a two-level surface relief, etched into the GaAs substrate beneath a bottom-emitting VCSEL. The combination generates a 4×4 array of focused spots 10 mm from the substrate with spot sizes down to less than 400 μm, almost at the diffraction limit. Diffraction efficiencies of 29% and uniformity errors of 14% were measured.