Nanophotonic Devices; Spontaneous Emission Faster than Stimulated Emission

Abstract : The goal of this project was to show that spontaneous emission could be accelerated by an optical antenna, to the point that it would become faster than stimulated emission. This would require spontaneous emission acceleration by 200x. The project has succeeded, both for optically pumped spontaneous emission, and electrically pumped spontaneous emission. We have observed a speedup of 300x, and we project a speedup of 2500xat an optimal antenna gap spacing, 10nm. We intend to present a publicity release based on this accomplishment. Actually, a narrower antenna gap would result in further speedup, but at progressively lower efficiency. The reason for this is that an oscillating atomic dipole induces optical frequency currents in the adjacent parts of the metal antenna. These currents are subject to Ohmic losses, cutting the antenna efficiency. Thus we have been encouraging our competitors to place a secondary requirement on spontaneous emission acceleration. It should be accompanied by antenna efficiency of 50%.