Optical slot antennas for enhancement of WSe2 spontaneous emission rate

The spontaneous emission rate of light emitters has been shown to have strong dependence on their local electromagnetic environment1. Optical antennas exploit this effect and can be used to greatly increase the spontaneous emission rate of a coupled light emitter. There have been several demonstrations of this effect with promising results using dye molecules and Er3+ ions2,3. It is predicted that spontaneous emission rate enhancements greater than 1000x can be achieved with optical antennas while maintaining greater than 50% optical efficiency4. Demonstration of large spontaneous emission enhancement of semiconductor light emitters could lead to low power, high efficiency, fast light sources useful for short-range optical communications. Transition metal dichalcogenides, such as WSe2, are promising candidates for the light emitter of such a nanoLED device because they are semiconductors that maintain good quantum efficiency even with a nanoscale dimension. In this work we demonstrate an optical slot antenna coupled to a monolayer of WSe2. Photoluminescence measurements show an increase of total light emission >700x when compared to WSe2 that is not coupled to an antenna. We estimate a spontaneous emission rate enhancement of 318x is responsible for this huge increase in light emission.