Superradiant diamond color center arrays coupled to concave plasmonic nanoresonators
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2019-10-14 |
| Journal | Optics Express |
| Authors | DĂĄvid Vass, AndrĂĄs Szenes, BalĂĄzs BĂĄnhelyi, Tibor Csendes, GĂĄbor SzabĂł |
| Institutions | University of Szeged |
| Citations | 7 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Superradiant Diamond Color Center Arrays
Section titled âTechnical Documentation & Analysis: Superradiant Diamond Color Center ArraysâExecutive Summary
Section titled âExecutive SummaryâThis research demonstrates the successful optimization of concave plasmonic nanoresonators (NRs) to achieve superradiantly enhanced emission from Silicon-Vacancy (SiV) color centers embedded in diamond. This work is highly relevant to the development of high-performance quantum information processing (QIP) platforms.
- Core Achievement: Optimized plasmonic coupling to SiV arrays resulted in a total fluorescence enhancement (Px factor) up to 2 x 106 and a corrected Quantum Efficiency (cQE) reaching 83%.
- Superradiance Confirmed: The optimized systems successfully achieved the superradiance threshold, exhibiting a radiated power proportional to N² (where N is the number of emitters).
- Material Superiority: Ellipsoidal bare diamond-silver NRs embedding 6 SiV centers proved the most suitable geometry, achieving a Purcell factor up to 104 at the excitation wavelength.
- QIP Relevance: The study confirms that MPCVD diamond is an ideal host for high-density, indistinguishable SiV emitters, crucial for realizing collective Dicke states and ultra-narrow linewidths required for quantum gates.
- Methodology: Conditional optimization using Finite Element Method (FEM) simulations (COMSOL Multiphysics) was used to design bad-cavities for maximizing the plasmonic Dicke effect (PDE).
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the optimization results, highlighting the extreme performance achieved through plasmonic coupling:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Px Factor (Total Fluorescence Enhancement) | 2 x 106 | a.u. | Achieved with 6 SiV centers in bare ellipsoidal NRs. |
| Maximum Purcell Factor (P) | 104 | a.u. | Achieved in bare ellipsoidal NRs (excitation wavelength). |
| Maximum Corrected Quantum Efficiency (cQE) | 83 | % | Achieved in bare ellipsoidal NRs (emission wavelength). |
| Excitation Wavelength (SiV) | 532 | nm | Green laser excitation. |
| Emission Wavelength (SiV) | 737 | nm | Near-infrared emission. |
| Radiative Rate Enhancement (dRem) | Up to 7 x 103 | a.u. | Achieved with 4 SiV centers in bare spherical NRs (emission). |
| Emitter Count (N) | 4 or 6 | centers | Arranged in symmetrical square or hexagonal patterns. |
| Polishing Requirement (Implied) | Ra < 1 | nm | Necessary for high-fidelity plasmonic interfaces and low scattering loss. |
Key Methodologies
Section titled âKey MethodologiesâThe research utilized advanced computational optimization techniques to design the nanoresonator structures for maximizing the plasmonic Dicke effect (PDE).
- Numerical Simulation: Finite Element Method (FEM) simulations, implemented via COMSOL Multiphysics, were used for conditional optimization.
- Emitter Model: SiV color centers were modeled as dipolar emitters, with oscillation aligned to the equatorial plane (excitation) and perpendicular to the long axis (emission).
- Nanoresonator Geometries: Concave core-shell structures were inspected, including:
- Spherical NRs (Bare: Diamond-Silver; Coated: Diamond-Silver-Diamond).
- Ellipsoidal NRs (Bare: Diamond-Silver; Coated: Diamond-Silver-Diamond).
- SiV Arrangement: Emitters were placed in symmetric arrays: square pattern (N=4) or hexagonal pattern (N=6).
- Optimization Criteria: The objective function was the cQE corrected quantum efficiency weighted Px factor (PxCQE), which is the product of radiative rate enhancements at excitation (Rex) and emission (dRem), multiplied by the corrected quantum efficiency (cQE).
- Superradiance Qualification: Superradiance was confirmed by normalizing the enhancement ratios (rX) against N and N² thresholds, demonstrating the required N² scaling of radiated power.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research highlights the critical need for high-quality, precisely engineered diamond substrates to serve as the host material for SiV color centers and as the dielectric component in complex plasmonic nanostructures. 6CCVD is uniquely positioned to supply the necessary materials and fabrication support to replicate and advance this work.
Applicable Materials
Section titled âApplicable MaterialsâTo achieve the narrow linewidths and high-density SiV arrays required for indistinguishable collective emission, the highest quality diamond is essential.
- Optical Grade Single Crystal Diamond (SCD): Recommended for hosting SiV centers. Our SCD material offers extremely low nitrogen and defect concentrations, minimizing inhomogeneous broadening and maximizing the intrinsic quantum efficiency (10% intrinsic QE was assumed in the paper).
- Custom SCD Substrates: We provide SCD plates with thickness control from 0.1Âľm up to 500Âľm. Precise thickness is crucial for controlling the dielectric shell thickness (t) and core radii (R) used in the optimized nanoresonators.
- Boron-Doped Diamond (BDD): While not the primary material for SiV, BDD is available for researchers exploring alternative plasmonic or conductive diamond interfaces, or for integration into electrochemical sensing platforms.
Customization Potential
Section titled âCustomization PotentialâThe complexity of the optimized core-shell nanoresonators (Ag/Diamond) and the need for precise SiV placement necessitate advanced material processing capabilities.
| Research Requirement | 6CCVD Capability | Technical Advantage |
|---|---|---|
| High-Fidelity Plasmonic Interfaces | Ultra-Low Roughness Polishing (Ra < 1nm) | Guaranteed SCD polishing (Ra < 1nm) is critical for minimizing scattering losses and maximizing the Purcell factor (up to 104) achieved in the NRs. |
| Custom Metalization Stacks | Internal Metalization Services (Au, Pt, Pd, Ti, W, Cu) | Although the paper used Ag, 6CCVD offers robust metal deposition capabilities. We can engineer multilayer stacks (e.g., Ti/Pt/Au) for improved adhesion and integration of plasmonic cores onto the diamond substrate. |
| Large-Area QIP Platforms | Custom Dimensions (PCD up to 125mm) | While SCD is preferred for SiV, our ability to produce large-area PCD wafers (up to 125mm) allows for scaling up related plasmonic or photonic crystal structures. |
| Precise Geometry Control | Laser Cutting and Shaping | We offer custom laser cutting services to achieve the specific spherical or ellipsoidal geometries required for the nanoresonators, facilitating subsequent focused ion beam (FIB) or etching processes. |
Engineering Support
Section titled âEngineering SupportâThe successful implementation of the plasmonic Dicke effect requires deep expertise in both diamond material science and quantum optics.
- Expert Consultation: 6CCVDâs in-house PhD team specializes in MPCVD diamond growth and defect engineering. We offer consultation on optimizing material selection, SiV implantation/growth recipes, and integration strategies for similar Superradiance and Quantum Information Processing (QIP) projects.
- Global Logistics: We ensure reliable global shipping (DDU default, DDP available) for sensitive, high-value diamond substrates, supporting international research collaborations.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Superradiantly enhanced emission of SiV diamond color centers was achieved via numerically optimized concave plasmonic nanoresonators. Advantages of different numbers of SiV color centers, diamond-silver (bare) and diamond-silver-diamond (coated) core-shell nanoresonator types, spherical and ellipsoidal geometries were compared. Indistinguishable superradiance is reached via four color centers, which is accompanied by line-width narrowing except in a coated ellipsoidal nanoresonator that outperforms its bare counterpart in superradiance. Seeding of both spherical and bare ellipsoidal nano-resonators with six color centers results in larger fluorescence enhancement and better overridden superradiance thresholds simultaneously. Both phenomena are the best optimized in a six color centers seeded ellipsoidal bare nanoresonator according to the pronounced bad-cavity characteristics.