Hybrid Plasmonic Bullseye Antennas for Efficient Photon Collection

TL;DR

This paper introduces hybrid plasmonic bullseye antennas that efficiently direct photon emission from quantum emitters into a narrow, highly directional beam, achieving significant decay rate enhancement and stable operation.

Contribution

The work presents a novel hybrid plasmonic antenna design that combines a titania grating and silver film, fabricated with standard lithography, enabling efficient, tunable, and stable photon collection from quantum emitters.

Findings

Achieved 85% photon collection efficiency into a 0.9 NA objective.

Demonstrated a decay rate enhancement close to 20 at the design wavelength.

Validated directional emission with NV-centers in experimental setup.

Abstract

We propose highly efficient hybrid plasmonic bullseye antennas for collecting photon emission from nm-sized quantum emitters. In our approach, the emitter radiation is coupled to surface plasmon polaritons that are consequently converted into highly directional out-of-plane emission. The proposed configuration consists of a high-index titania bullseye grating separated from a planar silver film by a thin low-index silica spacer layer. Such hybrid systems are theoretically capable of directing 85 % of the dipole emission into a 0.9 NA objective, while featuring a spectrally narrow-band tunable decay rate enhancement of close to 20 at the design wavelength. Hybrid antenna structures were fabricated by standard electron-beam lithography without the use of lossy adhesion layers that might be detrimental to antenna performance. The fabricated antennas remained undamaged at saturation laser powers exhibiting stable operation. For experimental characterization of the antenna properties, a fluorescent nanodiamond containing multiple nitrogen vacancy centers (NV-center) was deterministically placed in the bullseye center, using an atomic force microscope. Probing the NV-center fluorescence we demonstrate resonantly enhanced, highly directional emission at the design wavelength of 670 nm, whose characteristics are in excellent agreement with our numerical simulations.