Quantum memory and non-demolition measurement of single phonon state with nitrogen-vacancy centers ensemble
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-11-16 |
| Journal | Optics Express |
| Authors | Ruixia Wang, Kang Cai, Zhangâqi Yin, GuiâLu Long |
| Citations | 9 |
| Analysis | Full AI Review Included |
Technical Documentation and Analysis: Diamond for QND Single Phonon Memory
Section titled âTechnical Documentation and Analysis: Diamond for QND Single Phonon MemoryâExecutive Summary
Section titled âExecutive SummaryâThis documentation analyzes the application of Nitrogen-Vacancy (NV) centers ensemble (NVE) within diamond phononic crystals to realize quantum non-demolition (QND) measurement and quantum memory for single phonon states. This work is highly relevant to solid-state quantum computing and advanced quantum sensing, areas where 6CCVDâs high-purity chemical vapor deposition (CVD) diamond is essential.
- Core Achievement: Proposed scheme for QND measurement and quantum memory of a single phonon state using strain-induced NVE coupling in diamond.
- Mechanism: Strain-induced spin-phonon coupling is utilized, enhanced collectively by the NVE, reaching the strong coupling regime.
- Structure: Requires a diamond chip fabricated with a periodically arranged phononic crystal (rectangular holes) to precisely manipulate surface acoustic waves (SAW).
- Methodology: Adiabatic tuning of microwave and optical laser fields controls the NVE states for efficient phonon absorption and subsequent non-demolition detection via resonant frequency shift.
- Performance Metrics: Numerical simulations predict extremely high performance, including a 99.38% fidelity for the absorbing process and a 98.57% overlap between the input and output single phonon pulse shapes.
- Material Necessity: Success relies entirely on high-quality, ultra-low strain single crystal diamond (SCD) capable of hosting highly coherent, near-surface NV centers.
Technical Specifications
Section titled âTechnical SpecificationsâThe following parameters were utilized in the numerical simulations, defining the requirements for high-performance quantum phononic devices:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| NVE-Phonon Coupling Strength (g) | 2Ï x 5 | MHz | Coupling rate between single NV center and phonon |
| Rabi Frequency ($\Omega$0) | 2Ï x 290 | MHz | Applied microwave driving strength |
| Phonon Mode Frequency ($\omega$m) | 2Ï x 900 | MHz | Frequency of the mechanical resonance |
| Excited State Decay Rate ($\gamma$E) | 2Ï x 3 | MHz | Decay rate of the |
| Detuning ($\delta$) | 2Ï x 30 | MHz | Required detuning between energy levels |
| Effective Coupling Strength (gm / 2Ï) | 0.96 | MHz | Optimized value for >98% pulse overlap |
| Input/Output Phonon Overlap | 98.57 | % | Measure of QND measurement quality (for gm/2Ï = 0.96 MHz) |
| Absorption Process Fidelity (Ideal) | 99.38 | % | Fidelity of the state at the end of the absorption process (t=T) |
| Single Phonon Induced Frequency Shift ($\Delta$fs) | 2Ï x 43.26 | kHz | Shift detectable for QND measurement |
| Effective Dissipation Rate ($\gamma$e) | 2Ï x 2.16 | kHz | Calculated effective dissipation of the excited state |
| Effective Decay Rate ($\kappa$ / 2Ï) | 0.32 | MHz | Value used for high-fidelity simulations |
Key Methodologies
Section titled âKey MethodologiesâThe experimental scheme is built upon precise material fabrication and dynamic control:
- Diamond Phononic Crystal Fabrication: A diamond chip with periodically arranged rectangular holes is required to adjust the refractive index and control the resonant frequency of the Surface Acoustic Wave (SAW) phonons.
- NVE Placement: The Nitrogen-Vacancy Centers Ensemble (NVE) must be located a few ”m below the diamond surface to maximize coupling strength to the phonon modes while remaining optically accessible.
- Strain-Induced Coupling: Utilizing the strong, excited-state electron-phonon coupling mechanism (which is six orders of magnitude stronger than ground-state coupling) to mediate the interaction between the NVE and the mechanical mode ($\omega$m).
- Adiabatic Microwave Control (Absorption/Emission): Classical microwave driving (Rabi frequency $\Omega$) is adiabatically tuned to enable the NVE to perfectly absorb the input phonon (memory initialization) or emit a phonon pulse of a controlled shape (memory readout/source).
- QND Detection via Frequency Shift: After absorption, the driving pulse is stopped. An optical laser then probes the NV center/phonon system. The presence of a single absorbed phonon induces a measurable resonant frequency shift ($\Delta$fs) of the phononic crystal, allowing for non-demolition detection.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the advanced diamond materials required to realize and extend this groundbreaking research into quantum memory and QND measurement systems. Our expertise in MPCVD growth, precise material processing, and metalization ensures the delivery of substrates that meet the stringent requirements of quantum engineers.
Applicable Materials
Section titled âApplicable Materialsâ| Material Requirement in Paper | 6CCVD Material Solution | Specification Match |
|---|---|---|
| High-Purity Diamond Substrate (Host NV centers) | Optical Grade Single Crystal Diamond (SCD) | Ultra-low strain, high crystal purity essential for long coherence times (T2) and stable NV formation near the surface. |
| Phononic Crystal Substrate | Custom Dimension SCD Wafers | Available in plates/wafers up to 125mm. Required material thickness (0.1 ”m to 500 ”m) is available for optimal SAW/NVE proximity. |
| Potential Electrode/Transducer Requirements (SAW generation/detection) | PCD Substrates (High Thermal/Mechanical Stability) | For robust mechanical resonators requiring high stiffness and thermal management. |
Customization Potential
Section titled âCustomization PotentialâThe experimental design necessitates precise control over both bulk material quality and surface geometry, areas where 6CCVD excels:
- Precision Wafer Dimensions: We provide custom diamond wafers up to 125mm in diameter, necessary for scaling up phononic crystal designs and NVE arrays.
- Thickness Control for Near-Surface NVE: 6CCVD delivers highly uniform SCD plates down to 0.1 ”m thickness, critical for ensuring NVE location (a few ”m below the surface) maximizes strain coupling.
- Ultra-Smooth Surfaces: The fabrication of high-Q phononic crystals requires exceptionally low surface roughness. We guarantee Polishing: Ra < 1 nm for SCD substrates, ensuring minimal scattering losses for SAW phonons.
- Custom Metalization & Structuring: Although not fully detailed in the paper, SAW transducer applications typically require structured metal contacts. 6CCVD offers in-house deposition and patterning of standard metals, including Ti, Pt, Au, Pd, Cu, and W, necessary for electrical addressing or read-out circuitry.
- Phononic Crystal Fabrication Support: We supply the high-quality SCD blanks suitable for subsequent precise lithographic definition and etching of the rectangular holes (phononic crystal structures).
Engineering Support
Section titled âEngineering SupportâThis research demonstrates a complex interplay between electronic spin, mechanical vibration, and optical control. 6CCVDâs in-house team of PhD material scientists specializes in:
- NV Center Material Optimization: Assisting researchers in selecting the optimal SCD growth parameters (e.g., nitrogen concentration, growth rate) to achieve the required density and coherence properties for the NVE.
- Interface Engineering: Consulting on appropriate material preparation and metalization schemes to minimize damping and maximize strain coupling efficiency for similar Quantum Sensing and Optomechanical projects.
- Global Logistics: Ensuring prompt and reliable delivery of specialized diamond substrates worldwide (DDU default, DDP available).
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
In a diamond, the mechanical vibration-induced strain can lead to interaction between the mechanical mode and the nitrogen-vacancy (NV) centers. In this work, we propose to utilize the strain-induced coupling for the quantum non-demolition (QND) single phonon measurement and memory in a diamond. The single phonon in a diamond mechanical resonator can be perfectly absorbed and emitted by the NV centers ensemble (NVE) with adiabatically tuning the microwave driving. An optical laser drives the NVE to the excited states, which have much larger coupling strength to the mechanical mode. By adiabatically eliminating the excited states under large detuning limit, the effective coupling between the mechanical mode and the NVE can be used for QND measurement of the single phonon state. Under realistic experimental conditions, we numerically simulate the scheme. It is found that the fidelity of the absorbing and emitting process can reach a much high value. The overlap between the input and the output phonon shapes can reach 98.57%.