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Frequency Limits of Sequential Readout for Sensing AC Magnetic Fields Using Nitrogen-Vacancy Centers in Diamond
Santosh Ghimire1, Seong-Joo Lee1, Sangwon Oh1
1Quantum Magnetic Imaging Team, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea.
Sensors (Basel, Switzerland)
|September 9, 2023
Summary
We explored the frequency range for sensing alternating-current (AC) magnetic fields using nitrogen-vacancy (NV) centers in diamond. Optical repolarization, not decoherence, limits low-frequency sensitivity, enabling precise AC magnetic field measurements.
Area of Science:
- Quantum Sensing
- Diamond Quantum Technologies
- Condensed Matter Physics
Background:
- Nitrogen-vacancy (NV) centers in diamond are advanced quantum sensors.
- They offer high spatial resolution for detecting alternating-current (AC) magnetic fields.
- The full frequency range for AC sensing using dynamical decoupling (DD) remains underexplored.
Purpose of the Study:
- To experimentally determine AC magnetic field sensitivity as a function of frequency.
- To identify the limiting factors for AC sensing at high and low frequencies.
- To provide a predictive model for NV center AC magnetic field sensing performance.
Main Methods:
- Utilized a sequential readout method with nitrogen-vacancy (NV) centers in diamond.
- Investigated AC magnetic field sensitivity across various frequencies.
- Employed XY4-(4) dynamical decoupling (DD) sequences for sensing protocols.
Main Results:
- High-frequency sensitivity is limited by the Rabi frequency, influenced by DD pulse width.
- Low-frequency sensitivity is primarily governed by optical repolarization time, not decoherence (T2).
- Achieved a maximum sensitivity of 229 pT/Hz at 1 MHz using the XY4-(4) DD sequence.
Conclusions:
- The study clarifies frequency-dependent limitations in NV center AC magnetic field sensing.
- Optical repolarization duration is a critical factor for low-frequency sensing.
- The developed equation accurately describes the observed frequency dependence of sensitivity.
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