Lock-in Thermography Using Diamond Quantum Sensors
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-12-12 |
| Journal | Journal of the Physical Society of Japan |
| Authors | K. Ogawa, Moeta Tsukamoto, Kento Sasaki, Kensuke Kobayashi |
| Institutions | The University of Tokyo |
| Citations | 3 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research demonstrates a novel, non-contact lock-in thermography (LIT) technique utilizing Nitrogen-Vacancy (NV) centers in nanodiamonds for micrometer-scale thermal analysis.
- Core Technology: Lock-in thermography is implemented using NV centers dispersed as nanodiamonds (50 nm particle size) on the sample surface, enabling non-invasive temperature sensing.
- Key Achievement: Successful visualization of thermal diffusion dynamics and quantitative measurement of thermal diffusivity (α) in glass coverslips and Teflon (PTFE).
- Quantitative Validation: Thermal diffusivity derived from the amplitude decay of the temperature oscillation showed strong agreement with established literature values for both tested materials.
- High Sensitivity: The system achieved a temperature sensitivity of (297 ± 53) mK/sqrt(Hz).
- Versatility: Since the NV centers are spread as a thin layer, the method is applicable to various materials (insulators, semiconductors, metals) and arbitrary geometries.
- Future Potential: The technique offers the potential for spatial resolution down to the nanodiamond particle scale and frequency downconversion into the kHz-GHz band for advanced thermal dynamics studies.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| NV Center Temperature Coefficient | -74.2 | kHz/K | Zero-field splitting shift near room temperature |
| Nanodiamond Particle Size | 50 | nm | NDNV50nmHi10ml (Adamas Nanotechnologies) |
| Laser Wavelength | 515 | nm | Excitation source for NV centers |
| Laser Output Power | 150 | mW | Total power irradiated onto the sample |
| Microwave Frequency (Center) | 2.87 | GHz | Used for Optically Detected Magnetic Resonance (ODMR) |
| Microwave Power (Input) | 33 | mW | Power uniformly irradiated via circular cavity antenna |
| CMOS Camera Resolution | 772 x 1032 | pixels | Used for fluorescence detection |
| Field of View (FOV) | 106 x 140 | ”m | Area mapped by the CMOS camera |
| AC Heating Voltage (LIT) | 3.2 | V | Applied to the 10 Ω heater resistor |
| Thermal Oscillation Frequency | 0.5 | Hz | Frequency used for lock-in measurement |
| Temperature Sensitivity | 297 ± 53 | mK/sqrt(Hz) | Achieved precision per pixel |
| Nanodiamond Layer Thickness | 212 ± 77 | nm | Estimated thickness on the coverslip (4 ± 1.5 layers) |
| Thermal Diffusivity (Glass, Amplitude) | 3.5 ± 1.5 x 10-7 | m2/s | Experimental result (Literature: 4.7 x 10-7 m2/s) |
| Thermal Diffusivity (Teflon, Amplitude) | 1.1 ± 0.57 x 10-7 | m2/s | Experimental result (Literature: 1.2 x 10-7 m2/s) |
Key Methodologies
Section titled âKey MethodologiesâThe lock-in thermography process relies on measuring the temperature-dependent shift of the NV centerâs zero-field splitting (ZFS) frequency, converted into temperature modulation amplitude and phase.
- Sample Preparation: Nanodiamonds (50 nm) were dispersed onto the sample surface (glass or Teflon) using spin coating at 1000 RPM until the solution dehydrated, resulting in a layer thickness of approximately 212 nm.
- Thermal Setup: The sample was placed in a cavity on a Printed Circuit Board (PCB). Heat was input from a 10 Ω chip resistor (heater) through a copper foil, and the opposite side of the copper foil served as a heat sink.
- AC Heating Protocol: An AC voltage (3.2 V) at 0.25 Hz was applied to the heater, generating a thermal oscillation frequency of 0.5 Hz in the sample.
- ODMR Measurement (Four-Point Method): Instead of acquiring the full ODMR spectrum, the temperature modulation (ÎŽT) was calculated efficiently using the photoluminescence (PL) contrast measured at four specific microwave frequencies (f1, f2, f3, f4) selected on the slopes of the ODMR spectrum.
- Data Acquisition and Synchronization: PL images were acquired with a 10 ms exposure time, alternating between microwave ON and OFF states. The microwave frequency was switched every 1150 data points (46 seconds), synchronized with the AC heating signal initialization.
- Lock-in Analysis: The time-resolved temperature modulation ΎT(x, t) was fitted to a sinusoidal curve. The spatial distribution of the resulting amplitude decay and phase evolution was analyzed using the one-dimensional heat diffusion equation (Equation 2) to extract the thermal diffusion length (xd) and thermal diffusivity (α).
Commercial Applications
Section titled âCommercial ApplicationsâThe demonstrated NV-center lock-in thermography provides a powerful, non-invasive tool for thermal management and characterization across several high-tech sectors.
- Semiconductor and Nanoelectronics:
- Failure Analysis: High-resolution mapping of localized hot spots and thermal gradients in miniaturized integrated circuits (ICs) and semiconductor devices.
- Thermal Design Validation: Quantifying thermal transport properties of novel packaging materials and thin films used for efficient heat removal.
- Advanced Materials Science:
- Thin Film Characterization: Non-contact measurement of thermal diffusivity in complex, layered, or anisotropic materials where traditional contact sensors are invasive or inaccurate.
- Phonon Engineering: Studying hydrodynamic phonon transport and thermal behavior in 2D materials (e.g., graphene) and nanostructures.
- Quantum Technology and Sensing:
- NV Center Development: Characterization and quality control of nanodiamonds and NV ensembles for use in quantum sensors, ensuring thermal stability and performance.
- Quantum Device Integration: Thermal management analysis for superconducting circuits and quantum computing components operating at various temperatures (above 150 K).
- Biosciences and Medicine:
- Intracellular Thermometry: Potential application for microscopic measurement of intracellular temperature and thermal dynamics in living cells, aiding in the understanding of metabolic and molecular activities.
View Original Abstract
Precise measurement of temperature distribution and thermal behavior in\nmicroscopic regions is critical in many research fields. We demonstrate lock-in\nthermography using nitrogen-vacancy centers in diamond nanoparticles. We\nsuccessfully visualize thermal diffusion in glass coverslip and Teflon with\nmicrometer resolution and deduce their thermal diffusivity. By spreading\ndiamond nanoparticles over the sample surface, temperature variation can be\nmeasured directly without any physical contact, such as lead wires, making it\npossible to visualize the micrometer-scale thermal behavior of various\nmaterials.\n
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
Section titled âReferencesâ- 2001 - Electrons and Phonons: The Theory of Transport Phenomena in Solids [Crossref]
- 2010 - Lock-in Thermography: Basics and Use for Evaluating Electronic Devices and Materials [Crossref]