Optical far-field super-resolution microscopy using nitrogen vacancy center ensemble in bulk diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2016-09-12 |
| Journal | Applied Physics Letters |
| Authors | Shen Li, Xiang-Dong Chen, Bo Wen Zhao, Yang Dong, Chong-Wen Zou |
| Institutions | University of Science and Technology of China, National Synchrotron Radiation Laboratory |
| Citations | 13 |
| Analysis | Full AI Review Included |
Technical Documentation: Super-Resolution Microscopy via NV Center Ensembles
Section titled âTechnical Documentation: Super-Resolution Microscopy via NV Center EnsemblesâThis document analyzes the research demonstrating far-field super-resolution microscopy using Nitrogen Vacancy (NV) center ensembles in bulk diamond, focusing on the material requirements and connecting them directly to 6CCVDâs advanced MPCVD diamond capabilities.
Executive Summary
Section titled âExecutive SummaryâThe research successfully establishes a robust, non-scanning platform for super-resolution imaging and quantum sensing using high-density NV center ensembles embedded in bulk diamond.
- Core Achievement: Realization of an optical far-field super-resolution microscope (MANP) utilizing the charge state conversion (CSD nanoscopy) of NV centers as near-field probes.
- Resolution Breakthrough: Achieved sub-10 nm spatial resolution (6.1 nm) for locating individual NV centers, corresponding to approximately 1/56 of the optical diffraction limit (341 nm).
- Material Requirement: Requires high-quality, low-strain Single Crystal Diamond (SCD) substrates capable of supporting high-dosage nitrogen ion implantation (1013 cm-2) and subsequent metal film deposition (Ti/Al, Cr).
- Mechanism: The local optical field transmitted through surface nanostructures is measured by detecting the intensity-dependent charge state conversion rate (NV- $\leftrightarrow$ NV0).
- Application Potential: The resulting Microscopy with Array of Near-field Probes (MANP) system offers a universal, nanoscale, multi-functional platform for quantum sensing (electromagnetic fields, temperature, pressure) and nanophotonics investigations.
- 6CCVD Value: 6CCVD provides the necessary ultra-high purity, low-strain SCD substrates, custom dimensions, and advanced surface preparation (polishing, metalization) critical for replicating and advancing this cutting-edge quantum technology.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results, highlighting the performance metrics achieved using the NV center ensemble in bulk diamond.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| NV Center Locating Resolution | 6.1 | nm | Achieved via Charge State Depletion (CSD) nanoscopy |
| Diffraction Limit (532 nm) | 341 | nm | Calculated limit (1.22λ / 2N.A.) |
| Resolution Improvement Factor | 1/56 | Ratio | Resolution relative to the diffraction limit |
| MANP Imaging Resolution | 197 | nm | Measured resolution when imaging a 190 nm slot in Ti/Al film |
| Nitrogen Implantation Dosage | 1013 | cm-2 | Used to create high-density NV ensembles |
| Nitrogen Implantation Energy | 15 | keV | Determines NV depth profile |
| Estimated NV Center Depth | 20 ± 7 | nm | Estimated using SRIM simulation |
| CSD Depletion Laser Wavelength | 532 | nm | Doughnut-shaped beam |
| CSD Depletion Laser Power (High Res) | 22 | mW | Used for 6.1 nm resolution demonstration |
| CSD Depletion Pulse Duration | 100 | ”s | Per initialization-depletion-detection cycle |
| Metal Film Thickness (Ti/Al) | 5 / 15 | nm | Nanostructure imaged by MANP |
| Metal Film Thickness (Chromium) | 22 | nm | Nanostructure imaged by MANP |
Key Methodologies
Section titled âKey MethodologiesâThe experiment relies on precise material preparation and a specialized optical sequence known as Charge State Depletion (CSD) nanoscopy.
- Material Preparation:
- Bulk diamond plates were used as the base material.
- High-density NV center ensembles were created via high-dosage nitrogen ion implantation (1013 cm-2) at 15 keV energy.
- Metal nanostructures (Titanium/Aluminum or Chromium films) were deposited onto the diamond surface for imaging targets.
- Optical Setup:
- A home-built scanning confocal microscope with a 0.95 numerical aperture objective was used.
- Laser beams were aligned, combined using dichroic mirrors (DMs), and focused onto the NV centers.
- The depletion beam (532 nm) was shaped into a doughnut profile using a vortex phase mask to achieve super-resolution.
- CSD Nanoscopy Cycle:
- Initialization: NV centers are initialized to the NV- charge state using a 637 nm laser.
- Depletion: A doughnut-shaped 532 nm depletion laser pulse (e.g., 22 mW, 100 ”s duration) is applied to convert NV- to the optically dark NV0 state.
- Detection: The remaining NV- population is detected using a 589 nm laser pulse (e.g., 0.1 mW, 10 ”s duration). Only photons emitted during this phase are counted.
- Image Generation:
- The resolution is determined by the depletion rate, which is power-dependent.
- Positive-CSD images (convenient for high-density imaging) are obtained by subtracting the direct-CSD signal from the confocal image signal.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research highlights the critical need for high-quality diamond substrates with exceptional surface properties and precise dimensional control. 6CCVD is uniquely positioned to supply the materials and engineering services required to replicate and extend this work into commercial quantum sensing platforms.
Applicable Materials
Section titled âApplicable MaterialsâTo achieve the high spatial resolution and robust performance demonstrated, the following 6CCVD materials are essential:
| Material Specification | 6CCVD Offering | Relevance to Research |
|---|---|---|
| Substrate Material | Optical Grade Single Crystal Diamond (SCD) | Ultra-low strain and high purity are mandatory for stable NV center spin coherence and charge state stability, especially under high-power laser excitation. |
| Surface Finish | SCD Polishing (Ra < 1 nm) | Essential for high-fidelity lithography required to define the metal nanostructures (Ti/Al, Cr) and minimize scattering losses in near-field detection. |
| Dimensions | Custom Plates/Wafers | We offer custom dimensions up to 125 mm diameter, allowing for scaling the MANP platform beyond the small âdiamond plateâ used in the experiment. |
| Doping/Implantation | Low-N SCD Substrates | Provides the ideal starting material for post-growth nitrogen ion implantation (15 keV, 1013 cm-2) and subsequent high-temperature annealing required to form shallow, high-density NV ensembles. |
Customization Potential
Section titled âCustomization Potentialâ6CCVDâs in-house engineering capabilities directly address the complex fabrication steps required for MANP development:
- Custom Metalization: The research utilized Ti/Al and Cr films for nanostructures. 6CCVD offers internal metalization services including Ti, Au, Pt, Pd, W, and Cu. We can provide substrates pre-patterned or coated with specific metal stacks optimized for plasmonic or near-field applications.
- Precision Machining: We offer laser cutting and shaping services to produce diamond plates with unique geometries or specific edge finishes required for integration into complex optical setups (e.g., mounting on piezo scanners).
- Thickness Control: The experiment relies on bulk diamond. 6CCVD provides SCD thicknesses ranging from 0.1 ”m up to 500 ”m, and substrates up to 10 mm thick, ensuring compatibility with various optical mounting and thermal management requirements.
Engineering Support
Section titled âEngineering SupportâThe successful implementation of NV-center-based super-resolution microscopy requires deep expertise in diamond material science and quantum defect engineering.
- Material Selection: 6CCVDâs in-house PhD team can assist researchers in selecting the optimal SCD grade (e.g., specific nitrogen concentration, orientation, and surface termination) to maximize NV creation yield and spin coherence time for similar Quantum Sensing and Nanophotonics projects.
- Surface Optimization: We provide consultation on surface preparation techniques necessary for achieving the ultra-low roughness (Ra < 1 nm) required for high-resolution near-field coupling between the NV centers and surface nanostructures.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We demonstrate optical far-field super-resolution microscopy using an array of nitrogen vacancy centers in bulk diamond as near-field optical probes. The local optical field, which transmits through the nanostructures on the diamond surface, is measured by detecting the charge state conversion of the nitrogen vacancy center. Locating the nitrogen vacancy center with a spatial resolution of 6.1 nm is realized with charge state depletion nanoscopy. The nanostructures on the surface of a diamond are then imaged with a resolution below the optical diffraction limit. The results offer an approach to build a general-purpose optical super-resolution microscopy technique and a convenient platform for high spatial resolution quantum sensing with nitrogen vacancy centers.