Directional Emission of Photons from Nanocrystal Quantum Dots Using A Hybrid Plasmonic-Dielectric Nanoantenna

We design a hybrid circular plasmonic-dielectric nanoantenna for collimation of light emission from nanocrystal quantum dots at room temperature in the near IR spectral range. We implement a two-dimensional k-space imaging technique to obtain the full spectral-angular response of the resonance modes of the hybrid nanoantenna. This method is also used to map the full spectral-angular emission from nanocrystal quantum dots positioned at the center of the hybrid nanoantenna. We achieve a record low 4° divergence angle with a contrast above 17 of the emission into the narrow beam direction compared to emission outside the beam. In addition, we show that the hybrid nanoantenna is operational down to the single quantum dot level and exhibits single photon emission. This is a proof of principal for a room-temperature based single photon source.