Extending coherence time of macro-scale diamond magnetometer by dynamical decoupling with coplanar waveguide...

Area of Science:

• Quantum sensing
• Diamond magnetometry
• Nitrogen-vacancy (NV) centers

Background:

• Quantum magnetometry sensitivity is limited by NV center quantity and coherence time.
• High, homogeneous microwave power density is crucial for sensitive magnetometers over large volumes.

Purpose of the Study:

• To demonstrate a novel microwave resonator and optical system for enhanced quantum magnetometry.
• To improve sensitivity by increasing microwave power density and extending NV center coherence time.

Main Methods:

• Utilized a microwave resonator to boost microwave field power density.
• Employed an optical system with a 1.4 × 10^-3 mm³ detection volume.
• Applied a decoupling pulse sequence (XY16) to extend spin coherence time.

Main Results:

• Achieved 48 ns Rabi oscillation, faster than NV center phase relaxation time.
• Extended spin coherence time (T₂) up to 27 times longer than spin echo.
• Demonstrated an AC magnetic field sensitivity of 10.8 pt/Hz^1/2.

Conclusions:

• The developed system significantly enhances quantum magnetometer sensitivity.
• Optimized microwave irradiation and extended coherence time are key for high-performance NV center magnetometry.
• This approach offers a promising pathway for advanced magnetic field sensing applications.