Structured Nanoaperture Vertical Cavity Surface-Emitting Lasers

We report nanoscale patterning of concentric ring-shaped metal corrugations around a subwavelength aperture in Ag deposited on the top facet of a vertical cavity surface-emitting laser. The presence of the patterned rings results in more than doubling the collected far-field power and a significant reduction in far-field angular width. These plasmonic aperture lasers thus have the unique property of both a small near-field spot and a relatively low beam divergence. Finite-difference time-domain simulations are consistent with the experimental results and show that the far-field pattern is highly sensitive to misalignment of the aperture and to the presence of multiple transverse laser modes.