Near-Infrared-Enhanced Charge-State Conversion for Low-Power Optical Nanoscopy with Nitrogen-Vacancy Centers in Diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-01-12 |
| Journal | Physical Review Applied |
| Authors | Xiang-Dong Chen, Shen Li, Ao Shen, Dong Yang, ChunâHua Dong |
| Institutions | Chinese Academy of Sciences, University of Science and Technology of China |
| Citations | 35 |
| Analysis | Full AI Review Included |
Near-Infrared Enhanced Charge State Conversion for Low Power Optical Nanoscopy in Diamond
Section titled âNear-Infrared Enhanced Charge State Conversion for Low Power Optical Nanoscopy in DiamondâThis technical documentation analyzes the research demonstrating the use of Near-Infrared (NIR) laser enhancement to significantly reduce the power requirements for Charge State Depletion (CSD) nanoscopy utilizing Nitrogen Vacancy (NV) centers in diamond. This advancement is critical for scaling quantum sensing and imaging applications, particularly in biological environments where low laser power is essential.
Executive Summary
Section titled âExecutive SummaryâThe following points summarize the core technical achievements and value proposition of the NIR-enhanced CSD nanoscopy technique:
- Resolution Achievement: Demonstrated nanoscale spatial resolution of 14 nm in NV center imaging.
- Power Efficiency: The total depletion laser intensity was reduced by approximately three orders of magnitude compared to traditional Stimulated Emission Depletion (STED) nanoscopy for similar resolution.
- Mechanism: A 780 nm NIR laser beam was used to highly enhance the charge state conversion rate (NV- $\leftrightarrow$ NV0), acting as a purely accelerating photon source.
- Low Power Operation: The optimized CSD nanoscopy operates with depletion laser power reduced by approximately 10 times, minimizing sample heating and photodamage, which is crucial for biological and high-fidelity quantum sensing.
- Laser Configuration: The technique successfully combined a doughnut-shaped 532 nm visible laser with a Gaussian-shaped 780 nm NIR laser for optimized charge state manipulation.
- Material Requirement: The method relies on high-quality CVD diamond substrates suitable for precise NV center creation and high-NA optical coupling.
Technical Specifications
Section titled âTechnical SpecificationsâThe following table extracts key quantitative data points from the research paper:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Spatial Resolution Achieved | 14 | nm | Optimized CSD nanoscopy |
| Total Depletion Intensity (Optimized) | 1.2 | MW/cm2 | Combined 532 nm and 780 nm beams |
| Depletion Power Reduction (vs STED) | ~3 orders | N/A | Intensity reduction for similar resolution |
| Visible Depletion Wavelength | 532 | nm | Doughnut-shaped beam (Recombination pump) |
| NIR Depletion Wavelength | 780 | nm | Gaussian-shaped beam (Conversion accelerator) |
| Optimized 532 nm Power | 0.02 | mW | Used in conjunction with 0.4 mW 780 nm laser |
| Optimized 780 nm Power | 0.4 | mW | Used in conjunction with 0.02 mW 532 nm laser |
| NV- Zero Phonon Line (ZPL) | 637 | nm | Fluorescence peak |
| NV0 Zero Phonon Line (ZPL) | 575 | nm | Fluorescence peak |
| Accelerated Conversion Rate | 0.34 | ”s-1 | Achieved with synchronized 532 nm and 780 nm pulses |
| Nitrogen Implantation Energy | 20 | KeV | Used for NV center creation |
Key Methodologies
Section titled âKey MethodologiesâThe experimental success hinges on precise material preparation and synchronized two-laser depletion:
- Material Preparation: A CVD diamond plate was used as the base material. NV centers were created via 20 KeV nitrogen ion implantation.
- Optical Setup: The setup utilized a high Numerical Aperture (NA = 0.95) objective to focus multiple synchronized laser beams onto the diamond sample.
- Beam Shaping: The 532 nm visible depletion laser was shaped into a doughnut profile (using a vortex phase mask) to create the spatial depletion region necessary for super-resolution. The 780 nm NIR laser was Gaussian-shaped.
- Charge State Initialization: A Gaussian 637 nm laser pulse was used to initialize the NV center to the NV0 (dark) charge state.
- Two-Laser Depletion Sequence:
- The doughnut-shaped 532 nm beam pumps the NV0 $\rightarrow$ NV- recombination process.
- The Gaussian-shaped 780 nm NIR beam is applied simultaneously (0 ns delay) to accelerate the second transition of the two-photon charge state conversion process (ionization/recombination).
- Detection: A 589 nm Gaussian laser pulse was used for charge state detection, monitoring the NV- fluorescence (637 nm phonon sideband) blocked by long-pass filters.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the high-quality diamond materials and custom engineering required to replicate, optimize, and scale this advanced CSD nanoscopy technique for quantum sensing and imaging applications.
| Research Requirement | 6CCVD Solution & Value Proposition |
|---|---|
| High-Purity CVD Diamond Substrate | Optical Grade Single Crystal Diamond (SCD): We provide high-purity, low-strain SCD material (0.1 ”m to 500 ”m thickness). This material is essential for minimizing background noise and maximizing the fidelity of NV spin state manipulation and detection required for CSD nanoscopy. |
| Large Area Imaging & Scaling | Custom Dimensions: While the paper used a small plate, 6CCVD offers SCD substrates up to 10 mm and Polycrystalline Diamond (PCD) wafers up to 125 mm in diameter, enabling the scaling of this low-power nanoscopy technique for industrial or large-scale quantum imaging. |
| Surface Quality for High-NA Optics | Ultra-Low Roughness Polishing: The use of a 0.95 NA objective demands exceptional surface quality. Our SCD material is polished to Ra < 1 nm, ensuring optimal laser coupling and minimal scattering losses, critical for achieving 14 nm resolution. |
| Integrated Quantum Devices | Advanced Metalization Services: For future extensions of this work (e.g., integrating microwave control for electron spin resonance measurements), 6CCVD offers in-house metalization capabilities including Au, Pt, Pd, Ti, W, and Cu deposition. |
| Material Optimization for NV Creation | Custom Nitrogen Doping: We can supply SCD with controlled nitrogen concentrations, optimized for subsequent external NV creation processes (like the 20 KeV implantation used in this study) or for in-situ growth of NV ensembles. |
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research into high-fidelity quantum sensing, we recommend:
- Optical Grade Single Crystal Diamond (SCD): High-purity, low-strain material is necessary to maintain the long coherence times and high optical quality required for NV center quantum applications.
Customization Potential
Section titled âCustomization Potentialâ6CCVD provides comprehensive customization services to meet the precise needs of super-resolution nanoscopy projects:
- Custom Dimensions: Supply of plates and wafers tailored to specific experimental setups.
- Precision Polishing: Guaranteed surface roughness of Ra < 1 nm on SCD for optimal optical performance.
- Global Logistics: Global shipping is available (DDU default, DDP available) to ensure timely delivery of critical materials worldwide.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house team of PhD material scientists and engineers specializes in MPCVD diamond growth and processing for quantum technologies. We offer expert consultation on material selection, doping levels, and surface preparation to optimize diamond substrates for low-power CSD nanoscopy and other nanoscale quantum sensing projects.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
The near-infrared (NIR) optical pumped photophysics of nitrogen vacancy (NV) center in diamond was experimentally studied by considering both the charge state conversion and stimulated emission. We found that the NIR laser can help to highly enhance the charge state conversion rate, which can be applied to improve the performance of charge state depletion nanoscopy. Using a doughnut-shaped visible laser beam and a Gaussian-shaped NIR laser beam for charge state manipulation, we developed a low power charge state depletion nanoscopy for NV center. A spatial resolution of 14 nm was achieved with the depletion laser intensity approximately three orders lower than that used for the stimulated emission depletion nanoscopy with NV center. With high spatial resolution and low laser power, the nanoscopy can be used for nanoscale quantum sensing with NV center. And our study on the charge state conversion can help to further optimize the NV center spin state initialization and detection.