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All-Optical Vector Magnetometry Based on Level Anticrossing Spectroscopy of Spin Centers in 4H-SiC

MetadataDetails
Publication Date2025-09-01
JournalJournal of Experimental and Theoretical Physics Letters
AuthorsK. V. Likhachev, M. V. Uchaev, M.M. Loginova, Igor P. Veyshtort, A. P. Bundakova
AnalysisFull AI Review Included

Technical Documentation & Analysis: All-Optical Vector Magnetometry in 4H-SiC

Section titled “Technical Documentation & Analysis: All-Optical Vector Magnetometry in 4H-SiC”

This document analyzes the presented research on all-optical vector magnetometry in 4H-SiC and outlines how 6CCVD’s expertise in MPCVD diamond materials can support, replicate, and extend this quantum sensing technology.


  • Novel Sensing Platform: The research demonstrates an all-optical vector magnetometer utilizing S = 3/2 vacancy centers (V2) in 4H-SiC, a promising alternative to traditional NV-diamond systems.
  • Microwave-Free Operation: A key advantage is the elimination of microwave power requirements, simplifying sensor design, reducing complexity, and preventing sample heating.
  • High Sensitivity Achieved: The system demonstrated high sensitivity for the longitudinal magnetic field component (Bz) better than 0.1 ”T/√(Hz) and angular sensitivity greater than 0.01 mT/√(Hz).
  • Accelerated Vector Measurement: The use of calibrated “modifying” magnetic fields (Bmod) significantly accelerates the determination of all three vector components (Bx, By, Bz).
  • High Spatial Resolution: The method achieves micron and submicron spatial resolution, making it highly applicable for non-invasive diagnostics in microelectronics and biomedical sensing.
  • Extreme Environment Potential: The SiC platform is confirmed as suitable for magnetometry applications in high-temperature and high-radiation environments, aligning with diamond’s intrinsic robustness.
  • 6CCVD Relevance: 6CCVD provides the high-purity SCD and large-area PCD substrates necessary to develop and integrate similar quantum sensing platforms, offering superior material quality and customization for commercialization.

The following hard data points were extracted from the research paper detailing the experimental setup and performance metrics:

ParameterValueUnitContext
Sensor Material4H-SiCCrystalV2 Vacancy Centers (S = 3/2)
Excitation Wavelength785nmLaser excitation source
Excitation Power150mWLaser power used
Spatial Resolution~1”mScanning confocal microscope resolution
Bz Sensitivity (Static Field)< 0.1”T/√(Hz)Sensitivity for longitudinal magnetic field component
Angular Sensitivity ($\theta, \phi$)> 0.01mT/√(Hz)Sensitivity for polar and azimuth angles
Electron Irradiation Energy2MeVUsed for creating vacancy centers
Electron Irradiation Fluence~1018cm-2Used for creating vacancy centers
Fine-Structure Splitting (2D)23.4 x 10-4cm-1Equivalent to 70 MHz
Operating Temperature300KRoom temperature operation
Modulation Field Amplitude10mTUsed for synchronous detection
Modulation Frequency~1kHzUsed for synchronous detection

The experiment relies on precise material engineering and advanced optical detection techniques:

  1. Material Preparation: 4H-SiC crystals with low nitrogen concentration were grown using the sublimation “sandwich method.” V2 vacancy centers (S = 3/2) were created by irradiating the crystal with 2-MeV electrons to a fluence of ~1018 cm-2.
  2. Optical Excitation and Detection: A 785 nm laser (150 mW) was used for photoluminescence (PL) excitation. The PL signal was collected via a confocal microscope (resolution ~1 ”m) and detected in the infrared range using an avalanche photodiode (APD) and a synchronous detector.
  3. Level Anticrossing (LAC) Spectroscopy: The sensor signal was detected as changes in PL intensity corresponding to spin level anticrossings in the ground state, measured by scanning a quasi-stationary magnetic field (B0) along the crystal’s c-axis (z-axis).
  4. Vector Field Determination: The full external magnetic field (Bext) vector was determined sequentially:
    • Bz was determined by the shift of the LAC1 and LAC2 points relative to the reference spectrum.
    • The transverse component (B$_{\perp}$) magnitude was determined by changes in the intensity of satellite lines (associated with 29Si hyperfine interaction).
    • The Bx and By projections were determined by introducing calibrated “modifying” magnetic fields (Bmod) along the x and y axes, significantly accelerating the measurement process.

6CCVD specializes in high-quality MPCVD diamond, providing the materials and engineering services required to advance quantum sensing platforms, including those based on vacancy centers in SiC or the industry-standard NV centers in diamond.

While this research utilized SiC, 6CCVD’s materials are essential for developing robust, high-performance quantum sensors, especially where superior coherence or large area coverage is required:

  • Optical Grade Single Crystal Diamond (SCD): Recommended for researchers seeking to implement the most advanced quantum magnetometry platforms (e.g., Nitrogen-Vacancy centers), offering superior spin coherence times and thermal management compared to SiC.
  • Optical Grade Polycrystalline Diamond (PCD): Ideal for scaling up sensor technology. PCD offers large-area coverage (up to 125 mm diameter) necessary for industrial applications like semiconductor device diagnostics and large-scale magnetic field mapping.
  • Boron-Doped Diamond (BDD): Available for applications requiring conductive or electrochemical properties, offering robust performance in harsh environments (high temperature, radiation) where SiC is also targeted.

The integration of quantum sensors into microelectronics requires precise material control and fabrication capabilities. 6CCVD offers full customization to meet the demands of this research:

Research Requirement6CCVD Customization Capability
High-Resolution ImagingPrecision Polishing: SCD wafers polished to Ra < 1 nm and inch-size PCD polished to Ra < 5 nm, ensuring minimal scattering losses for confocal microscopy and submicron resolution.
Sensor Integration DepthCustom Thickness Control: SCD and PCD layers available from 0.1 ”m to 500 ”m, allowing precise control over the active sensor layer depth for optimized sensitivity and spatial resolution.
On-Chip Field GenerationCustom Metalization: Internal capability to deposit thin films (Au, Pt, Pd, Ti, W, Cu) for creating on-chip Helmholtz coils or compensation structures required for generating the “modifying” fields (Bmod).
Large-Area Sensor ArraysCustom Dimensions: PCD plates available up to 125 mm in diameter, supporting the development of compact, integrated sensors for industrial platforms, as suggested by the authors.

6CCVD’s in-house PhD team provides authoritative professional support to accelerate your research:

  • Material Selection for Quantum Sensing: Our experts can assist researchers in selecting the optimal diamond material (SCD vs. PCD) and specifications (purity, orientation, doping) for similar All-Optical Vector Magnetometry projects, whether based on SiC or diamond NV centers.
  • Integration and Fabrication: We offer consultation on post-processing steps, including electron irradiation (to create vacancy centers) and surface termination, ensuring the final material meets the stringent requirements for quantum coherence and optical performance.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

An all-optical vector magnetometer based on paramagnetic color centers with the spin S = 3/2 in 4H-SiC silicon carbide is presented. The corresponding magnetometry method is based on level anticrossing spectroscopy and does not require the application of microwave power, unlike magnetometry based on optically detected magnetic resonance of nitrogen-vacancy centers in diamond. This eliminates sample heating and simplifies the design of the instrument. It has been shown that the use of “modifying” magnetic fields makes it possible to accelerate the measurement of external magnetic fields with high accuracy. Optical detection of level anticrossing signals in the infrared range provides micron and submicron spatial resolution, which makes the method promising for applications in microelectronics and biomedicine.