Temperature drift rate for nuclear terms of the NV-center ground-state Hamiltonian
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-09-18 |
| Journal | Physical review. B./Physical review. B |
| Authors | Vladimir V. Soshenko, Vadim Vorobyov, Stepan V. Bolshedvorskii, Olga R. Rubinas, I. S. Cojocaru |
| Institutions | P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Russian Quantum Center |
| Citations | 17 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis study investigates the systematic temperature-induced shifts in the nuclear spin energy levels of the Nitrogen-Vacancy (NV) center in diamond, a critical factor for high-power ensemble quantum sensors.
- Core Problem Addressed: High optical pumping power in ensemble NV sensors causes significant heating (up to 60 °C), leading to systematic shifts in the spin-related energy levels and potential sensor failure.
- Key Finding (Shift Rate): The temperature-dependent shift of the 14N nuclear spin transition is approximately 200 Hz/°C, a noticeable effect that must be accounted for in practical sensor designs.
- Dominant Mechanism: The shift is overwhelmingly dominated by the hyperfine interaction constant (A||), which changes at a rate of -188 ± 4 Hz/°C, primarily due to the temperature-induced deformation of electron orbitals.
- Secondary Mechanism: The contribution from the nuclear spin electric quadrupole moment (Q) is an order of magnitude less sensitive to temperature, shifting at -24 ± 4 Hz/°C.
- Methodology: The shift was measured experimentally using a pulsed sequence similar to nuclear recursive polarization, combining Optically Detected Magnetic Resonance (ODMR) with Radio Frequency (RF) spectroscopy.
- Practical Impact: The measured shift magnitude (about 8 kHz) is significant relative to the resonance linewidth, confirming that temperature compensation is mandatory for high-precision nuclear spin-based sensors (e.g., gyroscopes and magnetometers).
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| NV ODMR Temperature Shift Rate | ~70 | kHz/K | Used for sample temperature calibration |
| Maximum Sample Heating Observed | ~60 | °C | Under continuous-wave (CW) 532 nm laser excitation |
| Total 14N Nuclear Spin Shift Rate | ~200 | Hz/°C | Overall shift magnitude requiring compensation |
| Hyperfine Constant Shift Rate (âA||/âT) | -188 ± 4 | Hz/°C | Dominant contribution to nuclear shift |
| Quadrupole Moment Shift Rate (âQ/âT) | -24 ± 4 | Hz/°C | Secondary contribution; less sensitive to temperature |
| Measured Shift Magnitude (Ground State) | ~8 | kHz | Compared to resonance width |
| Laser Wavelength | 532 | nm | Optical pumping source |
| Laser Power | 3 | W | Focused onto a 0.05 mm spot |
| NV Concentration | ~1 | ppm | In bulk diamond sample (111 crystallographic axis) |
| Electron Spin Rabi Frequency | 2 | MHz | Typical performance |
| Nuclear Spin Rabi Frequency | 10 | kHz | Typical performance |
| Nitrogen-Carbon Distance (R) | 0.252 | nm | Used in theoretical calculation |
| Thermal Expansion Coefficient (dR/dT) | -2.52(2) x 10-5 | K-1 | Used in theoretical calculation |
Key Methodologies
Section titled âKey MethodologiesâThe experiment utilized a pulsed ODMR sequence on an ensemble of NV centers in bulk diamond to measure the nuclear spin transition frequency as a function of temperature.
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Sample and Setup:
- Sample: Diamond plate (1 ppm NV centers) polished perpendicular to the 111 crystallographic axis.
- Excitation: 3 W, 532 nm laser radiation, modulated using an Acousto-Optical Modulator (AOM) to control the duty cycle and, consequently, the sample temperature.
- Fields: Constant magnetic field applied along the 111 axis. Microwave (MW) field generated via coaxial loops (LC resonator); Radio Frequency (RF) field generated via a 2x10 loop antenna.
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Temperature Calibration:
- The sample temperature was varied by adjusting the cooling-down time (duty cycle) in the pulsed sequence.
- Temperature was calibrated in situ by measuring the shift of the central NV ODMR resonance peak, utilizing the known ODMR temperature sensitivity (~70 kHz/K).
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Pulsed Spectroscopy Sequence (Nuclear Recursive Polarization Cycle):
- Initialization: Green optical pump prepares the electron spin (ms) into the ms = 0 ground state manifold.
- Transfer: A MW Ï pulse transfers the population from ms = 0 to the ms = -1 manifold.
- Nuclear Manipulation: An RF Ï pulse is applied. If resonant with a nuclear transition in the ms = -1 manifold, it mixes the hyperfine levels.
- Readout Preparation: A subsequent optical pulse returns most population to ms = 0, preserving the nuclear spin state.
- Detection: A second MW Ï pulse is applied. If the RF pulse was resonant, the population affected by the RF transition will no longer participate in the second MW transition, resulting in a suppression of the final ODMR signal.
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Data Acquisition:
- A 2D scan was performed, sweeping the MW frequency (for ODMR) for each RF frequency, allowing simultaneous visualization of both resonances.
- Resonance positions were fitted with Lorentzian curves to precisely determine the center frequency shift relative to the temperature change.
Commercial Applications
Section titled âCommercial ApplicationsâThe detailed understanding of temperature drift in NV nuclear spin terms is crucial for developing robust, high-power quantum devices, particularly those relying on ensemble measurements.
- Quantum Sensing and Metrology:
- High-Precision Gyroscopes: Nuclear spin is used to enhance rotation sensing sensitivity [11,12]. Accurate temperature compensation is essential for maintaining precision in practical, heated environments.
- Magnetic Field Sensors (Magnetometers): Ensemble-based sensors that utilize nuclear spin transitions require compensation for thermal drift to avoid systematic errors.
- Quantum Information Processing:
- Room Temperature Quantum Registers: The stability of nuclear spin storage properties against temperature fluctuations is vital for reliable quantum memory [7,8,16].
- Non-Volatile Quantum Memory: Utilizing nuclear spin for long-lasting memory requires minimizing thermal decoherence and shifts [15].
- Bio-Imaging and Medical Applications:
- Nanodiamond-Based Sensors: Used for enhancing Magnetic Resonance Imaging (MRI) sensitivity via dynamical nuclear polarization [3,13,14]. Localized heating in biological environments necessitates thermal stability data.
- Systematics Estimation: The derived shift rates (âA||/âT and âQ/âT) provide necessary parameters for estimating and correcting systematic errors during spin initialization, manipulation, and readout in practical devices.
View Original Abstract
Nitrogen-vacancy (NV) center in diamond was found to be a powerful tool for various sensing applications. The main work horse of this center so far has been optically detected electron resonance. Utilization of the nuclear spin has the potential of significantly improving sensitivity in rotation and magnetic field sensors. Ensemble-based sensors consume quite a bit of power, thus requiring an understanding of temperature-related shifts. In this article, we provide a detailed study of the temperature shift of the hyperfine components of the NV center.