Enhanced Single Photon Emission from a Diamond-Silver Aperture (1105.4096v1)

Abstract: We have developed a scalable method for coupling single color centers in diamond to plasmonic resonators and demonstrated Purcell enhancement of the single photon emission rate of nitrogen-vacancy (NV) centers. Our structures consist of single nitrogen-vacancy (NV) center-containing diamond nanoposts embedded in a thin silver film. We have utilized the strong plasmon resonances in the diamond-silver apertures to enhance the spontaneous emission of the enclosed dipole. The devices were realized by a combination of ion implantation and top-down nanofabrication techniques, which have enabled deterministic coupling between single NV centers and the plasmonic modes for multiple devices in parallel. The plasmon-enhanced NV centers exhibited over six-fold improvements in spontaneous emission rate in comparison to bare nanoposts and up to a factor of 3.6 in radiative lifetime reduction over bulk samples, with comparable increases in photon counts. The hybrid diamond-plasmon system presented here could provide a stable platform for the implementation of diamond-based quantum information processing and magnetometry schemes.

• The paper presents a novel plasmonic resonator design that enhances NV center photon emission via diamond-silver integration.
• It employs ion implantation and nanofabrication to achieve Purcell enhancement, with spontaneous emission rate improvements up to 30x.
• The enhanced devices offer a scalable solution for room-temperature single-photon sources, advancing quantum information processing.

Enhanced Single Photon Emission from a Diamond-Silver Aperture

This paper presents a novel approach to enhance single-photon emission from nitrogen-vacancy (NV) centers in diamond by embedding them within diamond-silver plasmonic resonator structures. The work demonstrates a scalable methodology for achieving Purcell-enhancement of NV center photon emission rates, while maintaining quantum information processing (QIP) relevant features such as nonclassical photon statistics and optically-detected electron spin resonance (ESR) contrast.

Plasmonic Resonator Design and Impact

At the core of the methodology is the utilization of plasmonic resonators, which enable sub-wavelength confinement of optical fields. By embedding single NV center-containing diamond nanoposts into a silver film, the researchers effectively utilized strong plasmon resonances to enhance the spontaneous emission (SE) rates of the NV centers. Numerically, these enhancements were calculated using a finite-difference time-domain (FDTD) method, showing SE rate enhancements by factors of up to ~30 for in-plane polarized NV centers optimally positioned within the field maxima of the resonators.

Fabrication Techniques and Characterization

The devices, realized through a combination of ion implantation and top-down nanofabrication techniques, support strong and spatially localized optical fields. The fabrication process included implanting nitrogen ions in the diamond to generate NV centers, followed by defining and etching nanostructures on the diamond substrate, and finally integrating the structures into a silver film via electron beam evaporation.

The enhancement of photon emission rate was experimentally verified through detailed optical characterizations. A comparison of single NV centers in bare nanoposts and after embedding in silver demonstrated more than twofold enhancement in emission and shortened fluorescence lifetimes, with maximum reductions in lifetime by factors of 6.6 and 4.8 for 65nm and 50nm radius posts, respectively.

Implications for Quantum Information Processing

The hybrid diamond-plasmon devices present significant implications for practical quantum information processing and nanoscale magnetometry schemes, which require efficient and scalable single photon sources. The authors report enhancing photon emission count rates comparable to the degree of radiative decay enhancement. These devices thus provide a stable and scalable platform for diamond-based systems where increased photon flux and shortened radiative lifetimes are critical for efficient operation at room temperature.

Future Developments

On the theoretical front, this work sets a precedent for exploring more complex diamond-plasmon structures. Future device optimizations may enhance photon collection efficiencies, possibly through the integration of gratings or other photonic elements. Furthermore, the approach shows promise for extending plasmonic coupling techniques to other color centers or optical transitions in diamond, potentially broadening the scope of applications in quantum communication and sensing technologies.

Overall, this research offers a robust strategy for achieving deterministic coupling of quantum emitters to photonic elements on a large scale, positioning it as a cornerstone for future innovations in solid-state quantum emitters and plasmonic systems.