Magnetic Steganography Based on Wide‐Field Diamond Quantum Microscopy
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2025-05-12 |
| Journal | Advanced Optical Materials |
| Authors | Jungbae Yoon, Jugyeong Chung, Hyunjun Jang, Ji Eun Jung, Yuhan Lee |
| Institutions | Korea Institute of Science and Technology, Chosun University |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Magnetic Steganography using Wide-Field Diamond Quantum Microscopy
Section titled “Technical Documentation & Analysis: Magnetic Steganography using Wide-Field Diamond Quantum Microscopy”Executive Summary
Section titled “Executive Summary”This research successfully demonstrates a novel magnetic steganography technique leveraging the high sensitivity and spatial resolution of diamond Nitrogen-Vacancy (NV) centers in a wide-field quantum microscope setup.
- Core Achievement: Proof-of-principle demonstration of concealing digital information (pixel art, barcodes, QR codes) within optically indistinguishable microstructures composed of magnetic (Ni) and non-magnetic (Au) materials.
- Quantum Sensor: Utilized ensemble NV centers implanted at a shallow depth (15 ± 5 nm) within a high-quality Single Crystal Diamond (SCD) plate.
- High Resolution & Scalability: Achieved sub-micrometer spatial resolution (< 1 µm) over millimeter-scale imaging areas, suitable for large-area security and forensic applications.
- Imaging Optimization: Identified the Optically Detected Magnetic Resonance (ODMR) Contrast mapping mode as providing superior image quality for steganography applications compared to frequency shift or linewidth mapping.
- Speed Enhancement: Implemented a Continuous Wave (CW) dual driving scheme utilizing the NV qutrit states, resulting in a threefold reduction in required imaging time while maintaining high image fidelity.
- Material Requirement: Requires ultra-high purity, [100] oriented SCD substrates with exceptional surface finish for reliable shallow NV implantation and high-contrast fluorescence collection.
Technical Specifications
Section titled “Technical Specifications”The following hard data points were extracted from the experimental setup and results:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Diamond Material | Single Crystal Diamond (SCD) | N/A | Electronic Grade, [100] top face |
| Diamond Dimensions | 2 x 2 x 0.1 | mm³ | Thinned plate used as sensor |
| NV Center Depth | 15 ± 5 | nm | Ultra-shallow implantation depth |
| NV Center Density | ≈10 | ppm | Ensemble concentration |
| Excitation Wavelength | 532 | nm | Green laser (700 mW power) |
| Microwave Frequency | ≈2.9 | GHz | Used to drive NV spin transitions |
| External Magnetic Field (Bext) | ≈400 | G | Applied to separate Zeeman resonances |
| Spatial Resolution | < 1 | µm | Achieved by wide-field quantum microscopy |
| Microstructure Materials | Ni, Au | N/A | Ni (Magnetic), Au (Non-magnetic) |
| Minimum Feature Size | 1 x 1 | µm2 | Pixel art square dots |
| Imaging Speed Improvement | Factor of 3 | N/A | Achieved via CW Dual Driving |
| Surface Polishing Requirement | Ra < 1 | nm | Necessary for ultra-shallow implantation (Inferred) |
Key Methodologies
Section titled “Key Methodologies”The experimental success relied on precise material engineering and advanced quantum control techniques:
- Substrate Preparation: Commercial SCD plates (2 x 2 x 0.5 mm³) were sliced and thinned down to 100 µm thickness.
- NV Center Creation: Nitrogen (15N+) ions were implanted at 10 keV with a density of 1014 cm-2, followed by high-temperature annealing at 1200 °C to form the NV centers.
- Surface Stabilization: Oxygen termination was performed at 465 °C (200 sccm flow) to stabilize the negatively charged NV- state.
- Microstructure Fabrication: Electron Beam Lithography (EBL) was used to pattern the magnetic (Ni) and non-magnetic (Au) structures. Metal layers (10 nm Ti adhesive, 50 nm Au/Ni) were deposited via electron beam evaporation and lift-off.
- Wide-Field Microscopy: A custom setup utilized a Total Internal Reflection Fluorescence (TIRF) objective (N.A. = 1.49) to excite NV centers and an sCMOS camera to collect the photoluminescence (PL) signal.
- Quantum Control (Dual Driving): A Continuous Wave (CW) dual driving scheme was implemented using two independent microwave fields (≈2.9 GHz) to simultaneously drive the NV qutrit states (ms = 0 ↔ ms = ±1), significantly reducing measurement time.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”6CCVD is uniquely positioned to supply the foundational diamond materials and customization services required to replicate, scale, and advance this magnetic steganography research.
Applicable Materials for Quantum Sensing
Section titled “Applicable Materials for Quantum Sensing”To achieve the high-fidelity ODMR measurements and shallow NV implantation demonstrated in this paper, researchers require the highest quality diamond substrates.
- Material Recommendation: Optical Grade Single Crystal Diamond (SCD)
- Orientation: [100] orientation is available, matching the substrate used for optimal NV alignment and performance.
- Purity: Ultra-low nitrogen background is essential to control the ensemble NV density (≈10 ppm) and maximize coherence time.
- Thickness: 6CCVD supplies custom SCD thicknesses from 0.1 µm up to 500 µm, perfectly accommodating the 100 µm thin plate used in the experiment.
Customization Potential & Fabrication Support
Section titled “Customization Potential & Fabrication Support”The fabrication of the magnetic steganography samples requires precise dimensional control and specialized metalization, capabilities offered in-house by 6CCVD.
| Research Requirement | 6CCVD Customization Capability | Value Proposition |
|---|---|---|
| Ultra-Shallow Implantation (15 nm depth) | Precision Polishing: SCD surface roughness (Ra) < 1 nm. | A pristine surface is critical for minimizing implantation damage and ensuring high-yield, high-quality shallow NV centers. |
| Custom Dimensions (2 x 2 mm³) | Scalability: Plates/wafers available up to 125 mm (PCD) and custom SCD sizes. | Enables scaling of the wide-field quantum microscope field-of-view for industrial inspection and large-area security applications. |
| Microwave Circuitry (Omega-shaped Au waveguide) | Custom Metalization: Internal deposition of Au, Ti, Pt, Pd, W, Cu. | We can supply diamond substrates pre-metalized with the necessary Ti/Au layers, streamlining the integration of microwave delivery structures. |
| Microstructure Alignment | Laser Cutting & Shaping: Precision laser cutting services for complex geometries. | Ensures accurate alignment and integration of the diamond sensor plate with the external microwave waveguide and optical system. |
Engineering Support
Section titled “Engineering Support”The successful implementation of advanced quantum techniques, such as the CW dual driving scheme utilizing NV qutrit states, relies heavily on optimal material selection and preparation.
- Expert Consultation: 6CCVD’s in-house PhD team specializes in material science for quantum applications. We can assist researchers in selecting the ideal SCD grade, orientation, and surface preparation methods to optimize NV formation and maximize magnetic field sensitivity (S ∝ Δω / (C√R0)).
- Application Focus: We provide dedicated engineering support for projects involving quantum sensing, magnetic imaging, and advanced digital security/forensic science applications similar to the magnetic steganography demonstrated.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Abstract Magnetic steganography using wide‐field quantum microscopy based on diamond nitrogen‐vacancy (NV) centers is experimentally demonstrated. The method offers magnetic imaging capable of revealing concealed information otherwise invisible with conventional optical measurements. For a proof‐of‐principle demonstration of magnetic steganography, micrometer structures designed as pixel arts, barcodes, and QR codes are fabricated using mixtures of magnetic and non‐magnetic materials: Ni and Au. Three different imaging modes based on the changes in frequency, linewidth, and contrast of the NV’s electron spin resonance are compared and find that the last mode offers the best quality for reconstructing hidden magnetic images. By simultaneous driving of the NV’s qutrit states with two independent microwave fields, the imaging time is expedited by a factor of three. This work shows potential applications of quantum magnetic imaging in the field of image steganography.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
Section titled “References”- 2005 - Information Hiding: First International Workshop
- 2002 - in Optical Security and Counterfeit Deterrence Techniques IV