Quantum emitters coupled to circular nanoantennas for high brightness quantum light sources

Abstract: Engineering the directionality and emission rate of quantum light sources is essential in the development of modern quantum applications.In this work we use numerical calculations to optimize the brightness of a broadband quantum emitter positioned in a hybrid metal-dielectric circular periodic nanoantenna. The optimized structure features a photon collection efficiency of 74% (82%) and a photon flux enhancement of over 10 (6) into a numerical aperature of 0.22 (0.50) respectively, corresponding to a direct coupling into two types of multimode fibers. In order to enhance the emission rate, we present a new circular nanoantenna design where a quantum emitter is attached to a silver nanocone at the center of the antenna. After optimization, we find a collection efficiency of 61% (78%) into a numerical aperature of 0.22 (0.50), giving a brightness enhancement of 1000 (600) for an unpolarized emitter. The enhancements in both structures are broadband due to the low quality factor of the device and are therefore ideal for room-temperature sources. This type of a scalable design can be utilized towards on-chip, high brightness quantum light sources operating at room temperature.