NV nanodiamond doped fiber for magnetic field mapping
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-01-01 |
| Journal | EPJ Web of Conferences |
| Authors | Adam Filipkowski, Mariusz MrĂłzek, Grzegorz StÄpniewski, Mateusz Ficek, Dariusz Pysz |
| Institutions | University of Warsaw, Jagiellonian University |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research demonstrates a novel approach to distributed magnetic field sensing by volumetrically incorporating Nitrogen-Vacancy (NV) nanodiamonds into the core of an optical fiber.
- Core Innovation: Achieves distributed magnetic field sensing along a macroscopic fiber length (13 cm section demonstrated) by integrating NV-rich nanodiamonds directly into the 50 ”m fiber core.
- Remote Readout: Successfully transmits spin state information (NV fluorescence) over the fiber length, enabling remote optical readout of spatially variable magnetic field data at the fiber output.
- Fabrication Method: Utilizes a modified stack-and-draw fiber development method combined with dip-coating of NV-rich nanodiamonds (750 nm mean size) onto a glass rod.
- Sensing Mechanism: Magnetic field mapping is achieved by longitudinally scanning a localized microwave (MW) antenna along the fiber, recording Optically Detected Magnetic Resonance (ODMR) spectra at discrete positions.
- Performance: The sensor achieved a magnetic field sensitivity of 26.6 ”T/âHz, sufficient to localize the position of an external neodymium magnet source.
- Future Potential: The methodology is scalable and suggests future improvements through integration of electronic addressing systems to replace physical scanning, significantly shortening measurement time.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Fiber Core Diameter | 50 | ”m | Multimode fiber |
| Total Fiber Length Used | 35 | cm | Total length of the NV-doped fiber |
| Distributed Sensing Length | 13 | cm | Section scanned for ODMR mapping |
| Nanodiamond Particle Size | 750 | nm | Mean particle size (NV-rich diamonds) |
| Fiber Attenuation | 50 | dB/m | Measured at 780 nm wavelength |
| Excitation Wavelength | 532 | nm | Pump laser wavelength |
| Fluorescence Collection Range | 600 to 850 | nm | Collected via high-pass filter |
| Magnetic Field Sensitivity | 26.6 | ”T/âHz | Measured performance |
| ODMR Contrast | < 0.1 | % | Low contrast due to localized MW exposure |
| MW Antenna Width | 3 | mm | Central opening width for fiber insertion |
| Scanning Step Size | 5 | mm | Longitudinal step size for ODMR recording |
Key Methodologies
Section titled âKey MethodologiesâThe NV nanodiamond-doped fiber was fabricated using a modified stack-and-draw process, and distributed sensing was achieved via longitudinal scanning of the MW field.
- Nanodiamond Incorporation: An F2 glass rod (Schott) was coated via dip-coating deposition in a suspension of NV-rich nanodiamond particles (750 nm mean size).
- Cane Production: The coated glass rod (30 mm diameter) was drawn down into intermediate canes (0.5 mm diameter).
- Preform Assembly: A stack of 790 canes was assembled and drawn into a fiber core preform. This preform was then inserted into a glass tube with a lower refractive index to serve as the cladding.
- Final Fiber Drawing: The assembly was drawn into the final multimode fiber, resulting in a 50 ”m core with volumetrically distributed nanodiamonds.
- Optical Excitation: The 35 cm fiber was pumped at one end using a 532 nm laser, exciting NV centers along the entire length.
- Remote Readout: Fluorescence was collected at the opposite end of the fiber, filtered (600-850 nm), and measured.
- Distributed Sensing: A 3 mm wide MW resonant antenna, mounted on a translation stage, was scanned along a 13 cm section of the fiber in 5 mm steps.
- Magnetic Field Mapping: A cylindrical neodymium magnet was placed at a fixed position (4 cm distance). ODMR spectra were recorded at each antenna position, and the resulting spectral broadening was used to localize the magnetic field source.
Commercial Applications
Section titled âCommercial ApplicationsâThis technology is critical for applications requiring continuous, spatially resolved magnetic field monitoring over extended distances.
- Quantum Sensing Networks: Development of long-range, distributed sensor arrays for monitoring large-scale infrastructure (e.g., pipelines, power grids) where traditional point sensors are impractical.
- Spintronics and Magnetic Memory: Providing high-resolution, non-invasive magnetic field mapping necessary for optimizing and controlling magnetic switching operations in advanced memory or quantum computing architectures.
- Biomagnetism: Potential for creating flexible, high-density magnetic field probes for mapping weak biological fields (e.g., magnetoencephalography or magnetocardiography), provided sensitivity can be scaled toward fT levels.
- Structural Health Monitoring: Integration into composite materials or structures to detect stress or damage based on changes in local magnetic permeability or induced fields.
- Security and Surveillance: Creating covert perimeter monitoring systems capable of detecting and localizing magnetic signatures over long distances.
View Original Abstract
The advances in fluorescent diamond-based magnetic field sensors have led this technology into the field of fiber optics. Recently, devices employing diamond nanobeams or diamond chips embedded on an optical fiber tip enabled achieving fT-level sensitivities. Nevertheless, these demonstrations were still confined to operation over localized magnetic field sources. A new approach of volumetric incorporation of nanodiamonds into the optical fiber core enables optical fibers sensitive to magnetic field at any point along the fiber length. We show that information on the perturbed spin state of a diamond nitrogen-vacancy color center can be transmitted over a macroscopic length in an optical fiber, in presence of noise from large concentration of the color centers along the fiber. This is exploited in optical readout at the fiber output not only of the magnetic field value, but also spatially variable information on the field, which enables the localization of its source.