Simultaneous imaging of magnetic field and temperature using a wide-field quantum diamond microscope
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-03-25 |
| Journal | EPJ Quantum Technology |
| Authors | Yulei Chen, Zhonghao Li, Hao Guo, Wu Da-Jin, Jun Tang |
| Institutions | North University of China, Shanxi Normal University |
| Citations | 8 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research demonstrates a wide-field quantum diamond microscope capable of simultaneously imaging magnetic fields and temperature, offering a powerful tool for micro-scale device analysis.
- Core Achievement: Successful implementation of a wide-field imaging technique using Nitrogen-Vacancy (NV) centers in a CVD diamond to simultaneously map magnetic field (B) and temperature (T) distributions.
- High Sensitivity: The system achieves competitive sensitivities: 1.8 ”T/Hz1/2 for magnetic fields and 0.4 K/Hz1/2 for temperature.
- Imaging Performance: The microscope provides a high spatial resolution of 1.3 ”m (limited by optical diffraction) over a large Field of View (FOV) of 400 x 300 ”m2.
- Decoupling Methodology: Magnetic field and temperature effects are decoupled by simultaneously measuring the frequency shifts of the Optically Detected Magnetic Resonance (ODMR) spectra corresponding to all four possible NV orientations.
- Practical Validation: The system was successfully used for real-time monitoring of integrated cell heaters (showing B-field suppression) and for quality control analysis of Printed Circuit Board (PCB) wires and solder joints.
- Future Potential: The technique is suitable for applications requiring wide-field, high-spatial resolution, and real-time monitoring, such as chip failure detection and bio-information sensing.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Magnetic Field Sensitivity (η) | 1.8 | ”T/Hz1/2 | Photon shot noise-limited |
| Temperature Sensitivity | 0.4 | K/Hz1/2 | Photon shot noise-limited |
| Spatial Resolution | 1.3 | ”m | Restricted by optical diffraction limit |
| Field of View (FOV) | 400 x 300 | ”m2 | Imaging area (800 x 600 pixels) |
| Diamond Material | CVD (100) | Plate | Oriented plate |
| Diamond Thickness | 50 | ”m | Polished thickness |
| NV Concentration | ~1 | ppm | Estimated concentration |
| Excitation Wavelength | 532 | nm | Laser source |
| Fluorescence Collection Range | 650-800 | nm | Filtered range |
| Laser Power Density | 10 | W/mm2 | Used for imaging system |
| Bias Magnetic Field (B0) | 7.5 | mT | External magnetic bias applied |
| Microwave Power | 20 | dBm | Fed to diamond via antenna |
| ODMR Linewidth (ÎV) | 12 | MHz | Used in sensitivity calculation |
| ODMR Contrast (C) | 2.8 | % | Used in sensitivity calculation |
| Temperature Coefficient (ÎČT) | -74 | kHz/K | At room temperature (300 K) |
| Total Measurement Time | 200 | seconds | For full ODMR scan (4000 steps) |
Key Methodologies
Section titled âKey MethodologiesâThe simultaneous imaging relies on a wide-field quantum diamond microscope setup utilizing the unique properties of NV centers in diamond.
- Diamond Preparation: A 50 ”m thick, (100)-oriented CVD diamond chip with an NV concentration of approximately 1 ppm is used as the sensing layer.
- Optical Setup: The diamond is illuminated by a 532 nm laser (10 W/mm2 power density). The resulting NV fluorescence (650-800 nm) is collected through an objective lens and imaged onto a scientific complementary metal oxide semiconductor (sCMOS) camera.
- Spin Control: A resonance microwave field (20 dBm power) is applied via a microwave antenna to drive the spin transitions (ms = 0 â ms = ±1).
- Bias Field Application: An external bias magnetic field (B0 = 7.5 mT) is applied. This field is crucial for resolving the eight distinct ODMR lines corresponding to the four crystallographic orientations of the NV centers (NVa, b, c, d).
- ODMR Imaging Scan: The sCMOS camera is synchronized with the microwave source, which is swept from 2.5 to 3.2 GHz in 4000 steps. This process acquires a stack of images, where each pixel generates a complete ODMR spectrum.
- Decoupling B and T:
- Magnetic field shifts (Zeeman effect) are proportional to the difference between the two resonance frequencies ((f+ - f-)/2).
- Temperature shifts (thermal effect) are proportional to the average shift of the zero-field splitting (D) relative to the bias field ((f+ + f- - 2D)/2).
- By measuring the shifts for all four NV orientations simultaneously, the magnetic field vector components (Bx, By, Bz) and the scalar temperature (T) are algebraically decoupled and calculated for every pixel.
- Device Testing: The technique was validated by imaging the magnetic field suppression and thermal distribution of an integrated cell heater and by analyzing current density and thermal hotspots in PCB solder joints.
Commercial Applications
Section titled âCommercial ApplicationsâThis wide-field, high-resolution B/T imaging technology is highly relevant for quality control and failure analysis in several high-tech engineering sectors.
- Semiconductor and Microelectronics:
- Chip Failure Detection: Real-time monitoring of integrated circuits (ICs) to identify current leakage paths, short circuits, and localized thermal hotspots that lead to device failure.
- Thermal Management: Precise mapping of temperature distribution in microprocessors and power electronics to optimize cooling solutions and prevent thermal runaway.
- Printed Circuit Board (PCB) Manufacturing:
- Quality Control: Non-destructive inspection of PCBs to verify current density distribution in traces and assess the quality and integrity of solder joints (identifying faulty or cold joints based on thermal signature).
- Quantum Device Characterization:
- Sensor Development: Characterization and calibration of new quantum sensors, magnetic storage devices, and micro-scale magnetic components.
- Micro-Electromechanical Systems (MEMS):
- Device Dynamics: Monitoring carrier transport and thermal behavior in complex MEMS structures, such as micro-heaters used in advanced sensors (e.g., micro NMR gyroscopes).
- Materials Science:
- Fundamental Research: Simultaneous study of magnetic and thermal dynamics in novel materials, including investigations into material dynamics and phase transitions under extreme conditions.
View Original Abstract
Abstract Quantum sensing based on nitrogen-vacancy centers in diamond has shown excellent properties. Combined with the imaging technique, it shows exciting practicability. Here, we demonstrate the simultaneously imaging technique of magnetic field and temperature using a wide-field quantum diamond microscope. We describe the operating principles of the diamond microscope and report its sensitivity (magnetic field ${\sim}1.8~\mu \mbox{T/Hz}^{1/2}$ <mml:math xmlns:mml=âhttp://www.w3.org/1998/Math/MathMLâ> <mml:mo>âŒ</mml:mo> <mml:mn>1.8</mml:mn> <mml:mspace/> <mml:mi>ÎŒ</mml:mi> <mml:msup> <mml:mtext>T/Hz</mml:mtext> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>/</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> and temperature ${\sim}0.4~\mbox{K/Hz}^{1/2}$ <mml:math xmlns:mml=âhttp://www.w3.org/1998/Math/MathMLâ> <mml:mo>âŒ</mml:mo> <mml:mn>0.4</mml:mn> <mml:mspace/> <mml:msup> <mml:mtext>K/Hz</mml:mtext> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>/</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> ), spatial resolution (1.3 ÎŒ m), and field of view ( $400 \times 300~\mu \mbox{m}^{2}$ <mml:math xmlns:mml=âhttp://www.w3.org/1998/Math/MathMLâ> <mml:mn>400</mml:mn> <mml:mo>Ă</mml:mo> <mml:mn>300</mml:mn> <mml:mspace/> <mml:mi>ÎŒ</mml:mi> <mml:msup> <mml:mtext>m</mml:mtext> <mml:mn>2</mml:mn> </mml:msup> </mml:math> ). Finally, we use the microscope to obtain images of an integrated cell heater and a PCB, demonstrating its ability in the application of magnetic field and temperature simultaneously imaging at wide-field.