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. arXiv:1703.00163v2 [physics.optics] 1 May 2017

Single Photon Sources with Near Unity Collection Efficiencies by Deterministic Placement of Quantum Dots in Nanoantennas

“…We compare our results to detailed FDTD simulations 40 taking into account the broadband nature and random dipole orientation of the QDs and find good agreement between simulation and experiments, as is shown in Fig. 4c (for more details on the simulations refer to 28 ). Furthermore, we also Tapered Nanowire; 45 Photonic crystal cavities; 46 Bullseye nanoantenna.…”

“…Therefore a hybrid metal-dielectric bullseye nanoantenna that combines the advantages of metallic and dielectric antennas but with fewer drawbacks was recently developed. [26][27][28][29][30][31][32] In this structure (see Fig 1c) the photon source placed at the center emits into a dielectric layer that acts as a slab waveguide guiding the light radially outward towards the circular gratings. The parameters of the antenna are tuned in such a way that in the far-field the interference between the various diffracted waves occurs only at low angles thus resulting in a highly directional photon stream.…”

A Robust Coherent Single-Photon Interface for Moderate- NA Optics Based on SiV Center in Nanodiamonds and a Plasmonic Bullseye Antenna

“…Here, the fluorescence originates from coupling to radially propagating surface plasmons 32 as well as partly-waveguiding, where fluorescence is scattered into the far-field from the antenna. For an ideal dipole, a high-refractive index capping layer would further enhance the waveguiding effect, 31 while here the relatively large ND could take over the waveguiding up to the first metal ring. Note, that the detection efficiency could alter between settings with different objectives.…”

“…By placing the SiV − -center-containing ND on a bullseye antenna the otherwise lost emission is coherently directed upwards at every metal ring, therefore increasing the amount of detectable coherent photons. A detailed description of the working principle is found in 31 and. 32 This enables to map the emission of the whole back-focal plane of the objective onto a CCD camera.…”

Overcoming the Rate-Directionality Trade-off: A Room-Temperature Ultrabright Quantum Light Source

“…A few years ago, we suggested a solution to this trade-off by proposing a composite structure shown in Fig. 1B that combines a nanocone (used as a plasmonic resonator) and a cir- cular Bragg grating (used as an antenna) (23). In this composite structure the emission from an emitter would first couple to the plasmonic nanocone before coupling to the hybrid metaldielectric bullseye antenna which redirects the emission out-of-plane (23).…”