Research on Micro-Displacement Measurement Accuracy Enhancement Method Based on Ensemble NV Color Center
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-04-26 |
| Journal | Micromachines |
| Authors | Yuqi Liu, Zhonghao Li, Hao Zhang, Hao Guo, Ziyang Shi |
| Institutions | North University of China |
| Citations | 1 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research validates a method for significantly enhancing the accuracy of micro-displacement measurement using ensemble Nitrogen-Vacancy (NV) color centers in diamond.
- Core Value Proposition: Achieved high-precision micro-displacement detection by combining Continuous-Wave Optically Detected Magnetic Resonance (CW-ODMR) with a Magnetic Flux Concentrator (MFC).
- Resolution Achievement: The system demonstrated a displacement detection resolution of 25 nm.
- Accuracy Enhancement: The integration of the MFC resulted in a 24-fold increase in resolution compared to the system operating without the concentrator.
- Mechanism of Action: The MFC amplifies the magnetic field gradient change corresponding to the NV spin surface by approximately 24 times, allowing the system to maintain high sensitivity even under weak magnetic field conditions.
- System Stability: Experimental data confirmed that the MFC structure introduced no observable detrimental influence on the overall signal noise level (noise deviation was calculated at 0.334 mV).
- Practical Reference: The results provide a robust, practical reference for developing high-precision, room-temperature micro-displacement sensors based on diamond quantum ensembles.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Displacement Resolution (with MFC) | 25 | nm | System performance |
| Resolution Enhancement Factor | 24 | times | Compared to system without MFC |
| Magnetic Field Gradient Change Rate (with MFC) | 24 | times | Experimental comparison |
| NV Center Concentration | 3 | ppm | Ensemble diamond sample |
| NV Sample Dimensions | 2 x 2 x 0.5 | mm | Diamond size |
| Excitation Laser Wavelength | 532 | nm | CW-ODMR setup |
| Excitation Laser Power | 300 | mW | CW-ODMR setup |
| NV Ground State Zero-Field Splitting (D) | 2.87 | GHz | Intrinsic NV property at zero field |
| Permanent Magnet Material | N35-sintered | N/A | Cylindrical shape |
| Permanent Magnet Dimensions | r = 5, h = 2 | mm | Radius and thickness |
| Magnetic Flux Concentrator (MFC) Material | Permalloy | N/A | MFC construction |
| MFC Simulated Magnification | ~30 | times | Theoretical amplification |
| MFC Conical Bottom Diameter/Height | 15 / 15 | mm | MFC geometry |
| MFC Cylindrical Top Diameter/Height | 2 / 15 | mm | MFC geometry |
| Single Step Displacement (Test) | 0.05 | mm | Minimum step used for voltage curve |
| Modulation Frequency | 1 | kHz | Lock-in amplifier setting |
| System Noise Deviation | 0.334 | mV | Calculated noise floor |
| Magnetic Field Gradient (with MFC) Slope | -9.89 ± 0.22 | Gauss/mm | dB1/dZ linear fit |
| Magnetic Field Gradient (without MFC) Slope | -0.402 ± 0.009 | Gauss/mm | dB2/dZ linear fit |
Key Methodologies
Section titled âKey MethodologiesâThe experiment utilized a CW-ODMR setup combined with a permanent magnet and a permalloy MFC to measure micro-displacement via changes in the Zeeman splitting frequency.
-
System Setup and Alignment:
- A permanent N35-sintered cylindrical magnet was fixed on a horizontal moving displacement table (minimum step accuracy 0.01 mm).
- The permalloy MFC (conical/cylindrical shape) was aligned coaxially with the permanent magnet axis.
- The NV ensemble diamond sample (3 ppm) was positioned symmetrically between the two MFC parts.
-
Optical and Microwave Excitation:
- A 532 nm laser (300 mW) was directed onto the diamond surface via mirrors, lenses, and a dichroic mirror.
- A microwave source (N5183B) emitted a resonant signal via an antenna to promote electron spin reversal, generating a modulated fluorescence signal.
-
Displacement and Gradient Control:
- Micro-displacement was controlled by adjusting the horizontal position of the permanent magnet relative to the fixed diamond/MFC assembly.
- The magnetic field step was changed by adjusting the horizontal displacement to realize the magnetic field gradient induced by the spin system.
-
Signal Detection and Demodulation:
- Fluorescence was collected by a photodetector (APD130A2/M).
- The collected signal was input into a lock-in amplifier (modulation frequency 1 kHz, amplitude 1 V) for demodulation, yielding the first-order differential signal.
- The demodulated signal was monitored via an oscilloscope.
-
Comparative Analysis:
- The relationship between the Zeeman splitting frequency change (âÏ) and displacement (Z) was measured both with and without the MFC.
- The slope of the frequency-displacement curve (dâÏ/dZ) was calculated for both configurations (e.g., -23.4 MHz/mm with MFC vs. -0.91 MHz/mm without MFC).
- System resolution was determined by dividing the calculated system noise deviation (0.334 mV) by the system sensitivity (voltage amplitude change per displacement step).
Commercial Applications
Section titled âCommercial ApplicationsâThe enhanced NV-based micro-displacement technology is highly relevant for industries requiring non-contact, high-resolution metrology and quantum sensing capabilities at room temperature.
- Precision Manufacturing and Metrology:
- Calibration and control of ultra-fine positioning stages (e.g., in semiconductor lithography or wafer inspection).
- Non-contact displacement sensing for high-speed, high-accuracy feedback loops in industrial automation.
- Quantum Sensing and Magnetometry:
- Development of compact, highly sensitive vector magnetometers capable of operating in ambient conditions.
- Applications in magnetic imaging and gradient sensing where high spatial resolution is critical.
- Materials Science and Testing:
- Measurement of micro-strain, creep, and vibration in micro-mechanical structures (MEMS) with nanometer precision, overcoming limitations associated with piezoelectric ceramics (hysteresis, nonlinearity).
- Scientific Instrumentation:
- Integration into advanced research instruments requiring precise control and measurement of relative motion between components (e.g., scanning probe microscopy, quantum optics setups).
View Original Abstract
This paper builds a corresponding micro-displacement test system based on an ensemble nitrogen-vacancy (NV) color center magnetometer by combining the correlation between a magnetic flux concentrator, a permanent magnet, and micro-displacement. By comparing the measurement results obtained with and without the magnetic flux concentrator, it can be seen that the resolution of the system under the magnetic flux concentrator can reach 25 nm, which is 24 times higher than without the magnetic flux concentrator. The effectiveness of the method is proven. The above results provide a practical reference for high-precision micro-displacement detection based on the diamond ensemble.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
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