Temperature sensing with nitrogen vacancy center in diamond

At a Glance

Metadata	Details
Publication Date	2022-01-01
Journal	Acta Physica Sinica
Authors	Hao-Bin Lin, Shao-Chun Zhang, Dong Yang, Y. H. Zheng, Xiang-Dong Chen
Citations	2
Analysis	Full AI Review Included

Executive Summary

This analysis focuses on the use of Nitrogen-Vacancy (NV) centers in diamond as a robust, high-resolution quantum sensor for thermometry, suitable for engineering and biological applications.

Core Value Proposition: NV centers enable non-invasive temperature measurement with spatial resolution down to the nanoscale (50 nm), significantly surpassing the 10 µm limit of conventional sensors.
Sensing Mechanism: Temperature is determined by measuring the shift in the NV center’s Zero-Field Splitting (ZFS, D), which is highly sensitive to phonon coupling (temperature).
High Sensitivity Achieved: Utilizing advanced spin manipulation techniques (Coherent Control/Ramsey), sensitivities as high as 5 mK·Hz^-1/2 are achieved in bulk diamond, with indirect methods reaching 0.076 mK·Hz^-1/2.
Wide Operational Range: The sensor operates reliably across a broad thermal spectrum, from cryogenic temperatures (5.6 K) up to 700 K.
Biocompatibility and Integration: Diamond’s chemical stability and non-toxicity allow for successful integration into biological systems (intracellular thermometry) and electronic devices (on-chip thermal mapping).
Speed: Fast thermometry methods (three-point ODMR sampling) allow for time resolutions better than 10 µs, enabling real-time monitoring of transient thermal events.

Technical Specifications

Parameter	Value	Unit	Context
Zero-Field Splitting (D)	2.87	GHz	Base state (S=1) at room temperature.
Temperature Coefficient (dD/dT)	74.2(7)	kHz/K	Linear approximation near room temperature (280-330 K).
Operational Temperature Range	5.6 to 700	K	Measured range from liquid helium to high heat.
Spatial Resolution (Nanodiamond)	50	nm	Achieved using NV centers in nanodiamonds.
Spatial Resolution (Imaging)	Sub-micron	µm	Demonstrated in thermal imaging of integrated circuits.
Best Sensitivity (Coherent Control)	5	mK·Hz^-1/2	Bulk diamond (99.995% ¹²C).
Best Sensitivity (Indirect/Curie Point)	0.076	mK·Hz^-1/2	Diamond pillar, utilizing magnetic phase transition for indirect measurement.
Time Resolution (Fast ODMR)	< 10	µs	Achieved using three-point sampling ODMR method.
ZPL Wavelength	637	nm	Wavelength of the Zero Phonon Line fluorescence.
Laser Excitation Wavelength (Typical)	532	nm	Used for spin initialization (pumping).

Key Methodologies

The NV center’s temperature sensing relies on three primary techniques, often combined with advanced spin control for optimization:

Optically Detected Magnetic Resonance (ODMR) of Zero-Field Splitting (ZFS):
- Initialization: Use a 532 nm laser to pump the NV center spin state to the m_s=0 ground state.
- Microwave Application: Apply microwave radiation near the ZFS frequency (D ≈ 2.87 GHz).
- Detection: When the microwave frequency matches the m_s=0 to m_s=±1 transition, the fluorescence count rate drops.
- Thermometry: The temperature (T) is derived directly from the measured shift in the ZFS value (D(T)).
- Fast ODMR: For high time resolution (< 10 µs), a three-point sampling method is used to quickly fit the ODMR curve and extract D.
Coherent Spin Manipulation (Ramsey/Dynamical Decoupling):
- Principle: This technique converts the measurement of the frequency shift (D) into a highly sensitive phase measurement (φ).
- Procedure: Microwave pulses (e.g., π/2 pulses) are used to create spin superposition states. The accumulated phase shift (Δφ_D) is measured after a coherence time (T_coh).
- Noise Reduction: Dynamical Decoupling sequences (like CPMG) are used to suppress environmental noise, particularly magnetic field fluctuations (Zeeman splitting), thereby increasing the temperature sensitivity (proportional to 1/√T_coh).
All-Optical Zero Phonon Line (ZPL) Thermometry:
- Principle: Measures the shift of the NV center’s ZPL fluorescence peak (around 637 nm) as a function of temperature.
- Advantages: Simple experimental setup, fast measurement speed, and does not require microwave components.
- Limitations: Generally lower temperature precision compared to ODMR methods and primarily effective below 100 K.

Commercial Applications

The unique combination of high spatial resolution, stability, and biocompatibility makes NV diamond thermometry valuable across several high-tech sectors:

Micro- and Nano-Electronics:
- Thermal mapping of highly integrated circuits (e.g., GaN HEMTs, transistors) to identify localized hot spots and ensure device reliability.
- Measuring temperature gradients in micro-structures with sub-micron precision.
Life Sciences and Biomedicine:
- Intracellular thermometry in single cells (e.g., C. elegans, fibroblast cells) to study heat generation mechanisms related to drug response, metabolism, and protein stability.
- Non-invasive monitoring of biological processes due to diamond’s non-toxicity and chemical inertness.
Materials Science and Engineering:
- Precise measurement of thermal conductivity (W/mK) in novel or low-dimensional materials by coupling NV nanodiamonds to Atomic Force Microscope (AFM) tips.
- Monitoring phase transitions and chemical reactions at the nanoscale.
Quantum Sensing Technology:
- Development of multi-parameter quantum sensors capable of simultaneously measuring temperature, magnetic fields, and electric fields with high spatial and temporal resolution.

View Original Abstract

Temperature is the most intuitive and widespread in various physical quantities. Violent changes in temperature usually implies the appearing of fluctuations in physical properties of an object. Therefore, temperature is often an important indicator. With the development of science and technology, the scales in many fields are being more and more miniaturized. However, there are no mature temperature measurement systems in the case where the spatial scale is less than 10 μm. In addition to the requirement for spatial resolution, the sensor ought to exert no dramatic influence on the object to be measured. The nitrogen vacancy (NV) center in diamond is a stable luminescence defect. The measurements of its spectrum and spin state can be used to obtain the information about physical quantities near the color center, such as temperature and electro-magnetic field. Owing to its stable chemical properties and high thermal conductivity, the NV center can be applied to the noninvasive detection for nano-scale researches. It can also be used in the life field because it is non-toxic to cells. Moreover, combined with different techniques, such as optical fiber, scanning thermal microscopy, NV center can be used to measure the local temperatures in different scenarios. This review focuses on the temperature properties, the method of measuring temperature, and relevant applications of NV centers.

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Original Source

DOI: https://doi.org/10.7498/aps.71.20211822