Radiofrequency response of the optically detected level anti-crossing signal in NV color centers in diamond in zero and weak magnetic fields
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2022-01-18 |
| Journal | arXiv (Cornell University) |
| Authors | А. К. Дмитриев, A. K. Vershovskiĭ |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: RF Response of NV Centers in Diamond
Section titled “Technical Documentation & Analysis: RF Response of NV Centers in Diamond”Reference: A K Dmitriev and A K Vershovskii, 2022. Radiofrequency response of the optically detected level anti-crossing signal in NV color centers in diamond in zero and weak magnetic fields.
Executive Summary
Section titled “Executive Summary”This research successfully investigates the manipulation and enhancement of Level Anti-Crossing (LAC) signals in negatively charged Nitrogen-Vacancy (NV) centers in diamond using radiofrequency (RF) fields. The findings are critical for developing next-generation magnetic field sensors.
- Core Mechanism: The complex RF response structure observed in the zero magnetic field (MF) LAC signal is accurately explained by the Autler-Townes (AT) splitting effect.
- Enhanced Sensitivity: The study demonstrates the ability to control and optimize LAC signal parameters, achieving a central resonance slope (dIph/dB0) that is 2.3 times higher than the slope recorded without an RF field.
- Application Focus: This enhancement directly translates to significantly increased sensitivity for magnetic field sensors operating in zero and weak MF environments (< 5 G).
- Biomedical Relevance: The technique avoids the use of microwave (MW) excitation, eliminating local MW heating, which is a crucial requirement for non-invasive biomedical sensing applications.
- Material Foundation: The experiment relies on high-quality synthetic diamond substrates, electron-irradiated and annealed to achieve a high concentration of NV centers (3-4·1018 cm-3).
Technical Specifications
Section titled “Technical Specifications”The following hard data points were extracted from the experimental setup and results:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Crystal Dimensions | 0.3 x 0.3 x 0.1 | mm3 | Sample size used in the experiment |
| NV Center Concentration | 3-4·1018 | cm-3 | Average concentration after post-processing |
| Electron Irradiation Dose | 5·1018 | el/cm2 | Dose used for NV creation |
| Annealing Temperature | 800 | °C | Annealing performed in Argon atmosphere |
| Pumping Wavelength | 520 | nm | Diode laser source |
| Pumping Power | 15 | mW | Input laser power |
| Magnetic Field Range (Tested) | -5 to +5 | G | Range tested in the vicinity of zero field |
| RF Field Frequency (fRF) | 5.3 | MHz | Typical operating frequency for maximum response |
| Maximum Slope Enhancement | 2.3 | times | Increase in signal steepness (dIph/dB0) |
| LAC Signal Width (HWHM) | 2.9 ± 0.1 | G | Half-Width at Half-Maximum of the LAC signal |
| Transverse Splitting (σ) | (2π) 5 | MHz | Standard deviation of the transverse strain field parameter (E) |
Key Methodologies
Section titled “Key Methodologies”The experimental procedure combined advanced material preparation with precise optical and radiofrequency control systems:
- Substrate Preparation: Synthetic diamond (Element Six SDB 1085 60/70 grade) was used as the base material.
- NV Center Creation: NV centers were generated via electron beam irradiation (5·1018 el/cm2) followed by high-temperature annealing (800 °C) in an Argon atmosphere.
- Optical Pumping: A 520 nm diode laser (15 mW) was coupled into an optical fiber and directed onto the diamond crystal for continuous-wave optical pumping.
- Magnetic Field Control: A 3D system of Helmholtz coils was used to generate and precisely control the static magnetic field (B0) in the range of 0 to 10 G.
- RF Excitation: Quasi-resonant RF fields (fRF ≈ 5 MHz) were applied using custom resonant and non-resonant coils surrounding the crystal.
- Signal Detection: Fluorescence was collected via the same fiber, filtered (dichroic mirror and red glass filter), and detected by a silicon photodiode.
- Synchronous Detection: The signal was processed using synchronous detection (lock-in amplification) referenced either to:
- Magnetic Field (MF) modulation (USD-MM).
- RF Amplitude Modulation (AM) (USD-AM).
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”The research demonstrates the critical role of high-quality, engineered diamond substrates in achieving enhanced quantum sensing capabilities. 6CCVD is uniquely positioned to supply and customize the materials required to replicate, scale, and advance this research into commercial sensor prototypes.
| Applicable Materials & Requirements | 6CCVD Solution & Value Proposition |
|---|---|
| High-Purity Substrate for NV Creation | Optical Grade Single Crystal Diamond (SCD): This research requires ultra-low nitrogen content precursor material to ensure controlled NV formation and optimal spin properties. 6CCVD supplies high-purity SCD wafers with thicknesses from 0.1 µm up to 500 µm, ideal for maximizing coherence times and signal fidelity. |
| Custom Dimensions & Integration | Precision Fabrication Services: The paper utilized a small, custom 0.3 x 0.3 x 0.1 mm3 crystal. 6CCVD offers expert laser cutting and dicing services to produce custom dimensions for SCD and PCD plates up to 125 mm, ensuring perfect integration into compact RF and optical setups. |
| Surface Quality for Optical Interface | Advanced Polishing (Ra < 1 nm): Optimal fluorescence collection and minimal scattering losses are essential. Our SCD polishing achieves surface roughness (Ra) < 1 nm, significantly improving the signal-to-noise ratio (SNR) critical for detecting small LAC signals. |
| Future Sensor Integration (Strain/E-Field Control) | Custom Metalization Services: To extend this research to include transverse strain field (E) control, integrated electrodes are necessary. 6CCVD provides in-house metalization capabilities, including deposition of Au, Pt, Pd, Ti, W, and Cu, tailored to specific device geometries. |
| Scaling and High-Volume Production | Large-Area Polycrystalline Diamond (PCD): While SCD is used for fundamental studies, 6CCVD offers PCD wafers up to 125 mm in diameter for scaling up sensor arrays, providing a cost-effective path for commercialization of weak MF sensors. |
| Engineering Support | In-House PhD Team Consultation: 6CCVD’s material scientists can assist researchers in selecting the optimal diamond grade (e.g., specific nitrogen doping levels) and post-processing strategies (e.g., irradiation targets) to achieve the required NV concentration (3-4·1018 cm-3) for similar Zero/Weak Magnetic Field Sensing projects. |
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
The response of the level anti-crossing signal to a quasi-resonant radio-frequency field, which appears in a zero magnetic field at NV color centers in diamond, is investigated. It is shown that the complex structure of this response can be explained by the Autler-Townes splitting. The possibility of controlling the parameters of the level anti-crossing signal is considered. It is shown that the slope of the central resonance recorded in this structure upon low-frequency modulation of the external magnetic field can be 2.3 times higher than the slope of the resonance recorded in the absence of an RF field. Conclusions are drawn about the nature of the level anti-crossing effect arising in zero field in NV color centers in diamond.