Ultrabright Linearly Polarized Photon Generation from a Nitrogen Vacancy Center in a Nanocube Dimer Antenna
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-05-04 |
| Journal | Nano Letters |
| Authors | Sebastian K. H. Andersen, Shailesh Kumar, Sergey I. Bozhevolnyi |
| Institutions | University of Southern Denmark |
| Citations | 88 |
| Analysis | Full AI Review Included |
Technical Documentation & Quantum Grade Material Analysis: NV-Center Plasmonic Enhancement
Section titled âTechnical Documentation & Quantum Grade Material Analysis: NV-Center Plasmonic EnhancementâDocument Reference: Ultrabright Linearly Polarized Photon Generation from a Nitrogen Vacancy Center in a Nanocube Dimer Antenna (arXiv:1706.09874v1)
Prepared by: 6CCVD Material Science & Engineering Team
Section titled âPrepared by: 6CCVD Material Science & Engineering TeamâExecutive Summary
Section titled âExecutive SummaryâThe research successfully demonstrates a state-of-the-art single-photon source (SPS) utilizing a Nitrogen Vacancy (NV) center in a nanodiamond (ND) coupled to a deterministically assembled plasmonic silver nanocube dimer antenna.
- Record Purity and Brightness: Achieved an exceptionally pure SPS with a measured second-order correlation function value of g(2)(0) = 0.08, alongside a high detected photon rate of 850 kcps (asymptotic limit 914 kcps).
- Enhanced Performance: The two-cube dimer configuration resulted in a significant 6.6-fold enhancement of the detected photon rate at saturation, and a 3.28-fold enhancement of the excited state decay rate (Îł/Îł0).
- Strong Polarization: The plasmonic coupling induced strong linear polarization in the emission, achieving a polarization ratio (rpol) of 9 between the major and minor axes.
- Room Temperature Stability: The system demonstrated high stability under large pump powers, attributed to the low ohmic heating losses of the pristine monocrystalline silver nanocubes and strong radiative damping.
- Deterministic Assembly: Atomic Force Microscopy (AFM) was successfully employed for pre-characterization of the NV dipole orientation and optimal alignment of the nanocube antenna for maximum NV-to-antenna coupling.
- Material Relevance: This work highlights the critical role of high-quality diamond (Nanodiamonds, NDs, in this case) as the host material for NV centers, a key component for room-temperature quantum technology applications (e.g., Quantum Key Distribution).
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Photon Rate (Detected) | 850 | kcps | Operating near saturation, 2-cube configuration |
| Asymptotic Photon Rate Limit (Râ) | 914 | kcps | Fitted saturation limit, 2-cube configuration |
| Single Photon Purity (g(2)(0)) | 0.08 | Dimensionless | 2-cube configuration (Record high purity) |
| Emission Polarization Ratio (rpol) | 9 | Dimensionless | Ratio of major to minor axes detected power |
| Excitation Wavelength | 532 | nm | Linearly polarized continuous wave or pulsed laser |
| NV-Center Emission (Simulated) | 680 | nm | Modeling wavelength for power dissipation |
| Excited State Decay Rate Enhancement (Îł/Îł0) | 3.28 | Factor | 2-cube relative to isolated 35 nm ND |
| Asymptotic Rate Enhancement (Râ/Râ0) | 6.58 | Factor | 2-cube relative to isolated 35 nm ND |
| Intrinsic Quantum Efficiency (qe0) | ~0.35 | Dimensionless | Assumed value for NV-center, based on FE model agreement |
| Nanodiamond (ND) Size | ~35 | nm | Contains the single NV-center |
| Plasmonic Antenna Material | Silver (Monocrystalline) | N/A | Low-loss material, large inter-band transition energy (~3.4 eV) |
| Nanocube Dimer Gap Size (Modeled) | 40-45 | nm | Realistic gap size for agreement with experimental results |
| Collection Objective NA | 1.4 | Dimensionless | Oil immersion objective |
Key Methodologies
Section titled âKey MethodologiesâThe highly optimized quantum source was realized through precise material selection and deterministic nanoscale assembly techniques, detailed below:
- Substrate Preparation: A 0.18 mm thick fused quartz glass slide was subjected to an RCA1 cleaning procedure to remove organic residue and promote surface hydrophilicity.
- Diamond Spin-Coating: A solution of nanodiamonds (ND) < 50 nm (Microdiamant) was spin-coated onto the prepared glass slide to ensure dispersed NV-center hosts.
- Antenna Deposition: 80 nm mean width monocrystalline silver nanocubes (nanoComposix), coated with a thin (< 5 nm) layer of polyvinylpyrrolidone (PVP), were deposited on the substrate.
- NV-Center Pre-Characterization: The dipole orientation of the isolated NV-center was determined by measuring the photon rate as a function of pump polarization angle (532 nm laser, 105 ”W power).
- Deterministic Assembly: An Atomic Force Microscope (AFM) was used for precise nano-manipulation, positioning two 80 nm silver cubes along the optimized dipole axis to form the dimer antenna, ensuring near-optimal coupling (measured alignment error: 15°).
- Excitation and Detection: The NV-center was excited using a 532 nm laser focused by a high-NA (1.4) oil immersion objective. Emitted photons were filtered (cut-off 550 nm) and analyzed via two Avalanche Photo Diodes (APDs) in a Hanbury Brown-Twiss (HBT) configuration to measure $g^{(2)}(\tau)$ and decay rates.
- Simulation & Modeling: 3D Finite Element Modeling (Comsol Multiphysics 5.1) was performed at 680 nm emission wavelength to calculate decay rate and collection efficiency enhancements, confirming the experimental findings based on an intrinsic quantum efficiency of 0.35.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD provides the specialized MPCVD diamond materials necessary to replicate, scale, and advance this high-performance quantum research, ensuring superior purity and surface quality required for demanding plasmonic integration.
Applicable Materials
Section titled âApplicable MaterialsâTo push the limits of NV-center performance, researchers require bulk-manufactured Single Crystal Diamond (SCD) that allows for scalable device fabrication (e.g., solid immersion lenses, integrated optics) rather than relying on heterogeneous nanodiamond solutions.
- Optical Grade Single Crystal Diamond (SCD): Required for applications relying on high-purity point defects. 6CCVD offers extremely low-nitrogen SCD, which can be custom-irradiated and annealed to create stable, highly coherent NV centers with low background fluorescence, crucial for maintaining the $g^{(2)}(0)$ purity demonstrated here.
- Ultra-thin SCD Membranes: For future integration into complex photonic chips, 6CCVD can supply SCD layers down to 0.1 ”m thickness, perfect for membrane-based quantum systems or suspended plasmonic structures.
Customization Potential for Quantum Device Integration
Section titled âCustomization Potential for Quantum Device IntegrationâThe paper achieved enhancement via externally placed nanocubes. Scaling this technology requires integrating these structures directly onto or within the diamond substrate, leveraging 6CCVDâs engineering capabilities.
| Service Category | 6CCVD Capability Relevance | Technical Advantage |
|---|---|---|
| Material Dimensions | Plates/wafers up to 125mm (PCD) | Enables scaling of device prototypes and high-volume fabrication of NV-based quantum circuits. |
| Surface Finish | Precision Polishing: Ra < 1 nm (SCD) | Critical for optimal coupling efficiency in near-field plasmonics (like the 40-45 nm gap used here) and integration with fabricated nanophotonic elements. |
| Integrated Contacts/Antennas | Custom Metalization: Au, Pt, Pd, Ti, W, Cu | Facilitates the lithographic definition of high-quality antennas and electrical contacts directly onto the SCD surface, moving beyond AFM-assembled external cubes. |
| Tailored Thickness | SCD thickness range: 0.1”m - 500”m | Supports the fabrication of Solid Immersion Lenses (SILs) or specific membrane thicknesses required for optical resonance or strain engineering. |
Engineering Support
Section titled âEngineering SupportâThe successful optimization of NV dipole orientation and antenna placement requires intimate knowledge of the host diamond material.
6CCVDâs in-house PhD team can assist with material selection and specification for projects aimed at replicating or extending this research, particularly in optimizing diamond purity and growth parameters (e.g., nitrogen concentration, post-growth treatments) necessary for high-yield, high-coherence NV-center creation in bulk SCD for advanced Quantum Key Distribution (QKD) and Optical Quantum Computing applications.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We demonstrate an exceptionally bright photon source based on a single nitrogen-vacancy center (NV center) in a nanodiamond (ND) placed in the nanoscale gap between two monocrystalline silver cubes in a dimer configuration. The system is operated near saturation at a stable photon rate of 850 kcps, while we further achieve strongly polarized emission and high single photon purity, evident by the measured autocorrelation with a g<sup>(2)</sup>(0) value of 0.08. These photon source features are key parameters for quantum technological applications, such as secure communication based on quantum key distribution. The cube antenna is assembled with an atomic force microscope, which allows us to predetermine the dipole orientation of the NV center and optimize cube positioning accordingly, while also tracking the evolution of emission parameters from isolated ND to the one- and two-cube configuration. The experiment is well described by finite element modeling, assuming an instrinsic quantum efficiency of 0.35. We attribute the large photon rate of the assembled photon source, to increased quantum efficiency of the NV center and high antenna efficiency.