Improved emission of SiV diamond color centers embedded into concave plasmonic core-shell nanoresonators
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-10-17 |
| Journal | Scientific Reports |
| Authors | AndrĂĄs Szenes, BalĂĄzs BĂĄnhelyi, LĂłrĂĄnt Zs. SzabĂł, GĂĄbor SzabĂł, Tibor Csendes |
| Institutions | University of Szeged |
| Citations | 25 |
| Analysis | Full AI Review Included |
Technical Documentation & Collateral: Enhanced SiV Emission via Plasmonic Core-Shell Resonators
Section titled âTechnical Documentation & Collateral: Enhanced SiV Emission via Plasmonic Core-Shell ResonatorsâExecutive Summary
Section titled âExecutive SummaryâThis document analyzes the numerical optimization of concave plasmonic core-shell nanoresonators (using a diamond core hosting Silicon Vacancy (SiV) centers and a Silver shell) designed to maximize fluorescence enhancement for solid-state quantum systems.
- Record Enhancement Achieved: The methodology yielded total fluorescence enhancement (Pâ factor) up to $8.34 \cdot 10^{5}$-fold using optimized rod-shaped resonators.
- Simultaneous Tuning: Optimization successfully tuned transversal and longitudinal dipolar plasmon resonances to align simultaneously with both the SiV excitation ($\approx$532 nm) and emission ($\approx$738 nm) wavelengths.
- High Quantum Efficiency (cQE): Conditional optimization ensured a high corrected apparent quantum efficiency, peaking at 57.5% (DSCS configuration), representing an approximately 5-fold enhancement over the intrinsic SiV QE (10%).
- Material Foundation: The core element, the diamond substrate, provides the stable, robust host material necessary for SiV color center embedding and operation in quantum information processing (QIP).
- Optimal Geometry: Decentralized ellipsoidal (DECS) and rod-shaped (DRCS) geometries were significantly superior to spherical configurations, leveraging antenna-like properties for increased radiative rate enhancement.
- 6CCVD Value Proposition: 6CCVD provides the foundational single-crystal diamond (SCD) material, custom metalization, and polishing necessary to replicate and extend this high-performance solid-state quantum architecture.
Technical Specifications
Section titled âTechnical SpecificationsâThe following table summarizes the key performance indicators (KPIs) and material parameters identified in the optimization of the coupled dipole-nanoresonator systems.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Max Pâ Factor (Total Fluorescence Enhancement) | $8.34 \cdot 10^{5}$ | Fold | Optimized Decentralized Rod-Shaped (DRCS) |
| Max cQE (Apparent Quantum Efficiency) | 57.5 | % | Optimized Decentralized Spherical (DSCS) |
| Intrinsic SiV QE (QEâ) | 10 | % | Assumed baseline quantum efficiency for SiV |
| DECS Pâ Factor | $6.2 \cdot 10^{5}$ | Fold | Decentralized Ellipsoidal Geometry |
| DRCS Radiative Rate Enhancement (Emission, R$^{rad}_{emission}$) | 2150 | Fold | Longitudinal dipolar resonance |
| DRCS Radiative Rate Enhancement (Excitation, R$^{rad}_{excitation}$) | 388 | Fold | Transversal dipolar resonance |
| CSCS Pâ Factor | 529 | Fold | Centralized Spherical Geometry |
| Primary Diamond Defect | Silicon Vacancy (SiV) | N/A | Quantum Emitter Host |
| Shell Material | Silver (Ag) | N/A | Plasmonic Nanoresonator |
Key Methodologies
Section titled âKey MethodologiesâThe fluorescence enhancement was achieved via numerical optimization using a Finite Element Model (FEM) implemented in COMSOL Multiphysics, focusing on geometry and emitter placement.
- System Modeling: The SiV color center was approximated as a lossless, pure point-like electric dipole embedded within a diamond ($\text{C}$) dielectric core.
- Plasmonic Structure: The core was enclosed within a concave Silver ($\text{Ag}$) nanoshell, forming a core-shell nanoresonator.
- Optimization Objective: The optimization algorithm (in-house GLOBAL algorithm) maximized the Pâ factor, defined as the product of the radiative rate enhancements at the excitation and emission wavelengths ($P_x = R^{rad}{excitation} \cdot R^{rad}{emission}$).
- Conditional Constraint: Optimization included a conditional constraint requiring the corrected apparent quantum efficiency (cQE) to exceed a specified threshold (e.g., $\ge$ 50%) at the emission wavelength.
- Variable Parameters: Optimization was performed by varying geometric parameters, specifically the core radius ($r_1$), shell thickness ($t$), aspect ratio (for non-spherical shapes), and the dipole displacement ($\text{dx}, \text{dy}$) from the center.
- Inspected Geometries: Four configurations were analyzed to exploit different plasmonic effects:
- Centralized Spherical Core-Shell (CSCS).
- Decentralized Spherical Core-Shell (DSCS).
- Decentralized Ellipsoidal Core-Shell (DECS).
- Decentralized Rod-like Core-Shell (DRCS).
- Far-Field Analysis: Calculations analyzed the Purcell factor, QE, scattering cross-sections, near-field $\text{E}$-field distribution, and surface charge density to understand the coupling mechanisms (bonding/antibonding and multipolar resonances).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research demonstrates the critical role of high-quality diamond substrates in realizing next-generation solid-state quantum emitters. 6CCVD is uniquely positioned to supply the foundational SCD material and advanced fabrication services required to replicate and scale these optimized nanophotonic architectures.
Applicable Materials
Section titled âApplicable MaterialsâThe SiV center requires an ultra-pure, low-defect environment. 6CCVD strongly recommends:
- Optical Grade Single Crystal Diamond (SCD): Required for SiV quantum emitters. Our high-purity MPCVD SCD ensures minimal nitrogen incorporation (to prevent competing NV centers) and low strain, which is crucial for maintaining the uniquely narrow spectral lines and advantageous relaxation time of SiV centers.
- Standard Thicknesses: We provide SCD wafers in the optimal thickness range (typically 0.1 ”m to 500 ”m) needed for subsequent etching, nanofabrication, and SiV implantation processes.
Customization Potential
Section titled âCustomization PotentialâReplicating the highest-performing geometries (Ellipsoidal and Rod-like Core-Shells) requires highly precise material shaping and metal deposition. 6CCVDâs specialized services align perfectly with these requirements:
| Research Requirement | 6CCVD Capability | Specification |
|---|---|---|
| Diamond Core Fabrication | Custom substrate growth and post-processing | Plates/wafers up to 125mm in size, customized thickness (up to 10mm). |
| Epitaxial Layer Quality | SCD Growth Purity | Low-Nitrogen concentration necessary for high-fidelity SiV formation and long coherence times. |
| Surface Finish | High-Quality Polishing | Ra < 1nm is available for SCD surfaces, minimizing scattering loss and enabling high-precision nanofabrication. |
| Plasmonic Shell Deposition | Internal Metalization Services | While Ag was used in the study, 6CCVD offers custom thin-film deposition of Au, Pt, Pd, Ti, W, and Cu, allowing researchers to explore material hybridization effects and optimize plasmonic performance further. |
| Complex Geometry | Advanced Fabrication Support | Our team assists with material selection for subsequent shaping processes (e.g., focused ion beam etching or RIE) required to form the critical nano-ellipsoidal and rod-like core geometries. |
Engineering Support
Section titled âEngineering SupportâThe simultaneous enhancement of excitation and emission radiative rates is essential for high-efficiency solid-state quantum light sources.
- 6CCVDâs in-house PhD-level engineering team specializes in the material science of diamond defects and MPCVD growth parameters tailored for Quantum Information Processing (QIP) and integrated nanophotonics.
- We offer consultation on selecting the optimal starting diamond grade, determining the required thickness, and advising on metalization stacks (e.g., Ti/Pt/Au adhesion layers) for projects targeting enhanced fluorescence or single-photon emission from SiV, NV, or other diamond color centers.
Call to Action
Section titled âCall to ActionâTo achieve optimal material performance for demanding applications like enhanced SiV fluorescence or quantum nanophotonics, material quality cannot be compromised. For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Abstract Configuration of three different concave silver core-shell nanoresonators was numerically optimized to enhance the excitation and emission of embedded silicon vacancy (SiV) diamond color centers simultaneously. Conditional optimization was performed to ensure ~20-30-40 and 50% apparent quantum efficiency ( cQE) of SiV color centers. The enhancement spectra, as well as the near-field and charge distribution were inspected to uncover the underlying nanophotonical phenomena. The conditionally optimized coupled systems were qualified by the product of the radiative rate enhancements at the excitation and emission, which is nominated as P x factor. The optimized spherical core-shell nanoresonator containing a centralized emitter is capable of enhancing the emission considerably via bonding dipolar resonance. The P x factor is 529-fold with 49.7% cQE at the emission. Decentralization of the emitter leads to appearance of higher order nonradiative multipolar modes. Transversal and longitudinal dipolar resonance of the optimized ellipsoidal core-shell resonator was tuned to the excitation and emission, which results in 6.2â10 5 P x factor with 50.6% cQE at the emission. Rod-shaped concave core-shell nanoresonators exploit similar transversal and longitudinal dipolar resonance, moreover they enhance the fluorescence more significantly due to their antenna-like geometry. P x factor indicating 8.34â10 5 enhancement is achievable while the cQE is 50.3% at the emission.