A robust scanning diamond sensor for nanoscale imaging with single nitrogen-vacancy centres

Area of Science:

• Quantum sensing
• Materials science
• Nanotechnology

Background:

• Nitrogen-vacancy (NV) centers in diamond are promising for nanoscale sensing and quantum technologies.
• Existing scanning methods using diamond nanocrystals have limitations in spin coherence and fluorescence collection.
• Precise positioning of NV centers near samples is crucial for advanced applications.

Purpose of the Study:

• To develop a robust scanning method for single NV centers.
• To overcome limitations of existing scanning probe techniques for NV center applications.
• To improve spin coherence times and fluorescence collection efficiency.

Main Methods:

• Utilizing a high-purity diamond nanopillar with a single NV center as an atomic force microscope tip.
• Positioning the NV center within tens of nanometers of a sample surface.
• Employing waveguiding for enhanced fluorescence collection.

Main Results:

• Achieved long NV spin coherence times of approximately 75 µs.
• Demonstrated enhanced fluorescence collection efficiencies.
• Successfully imaged magnetic domains with 25 nm widths.
• Attained a magnetic field sensitivity of 56 nT/√Hz at 33 kHz.

Conclusions:

• The diamond nanopillar method provides a robust platform for scanning NV centers.
• This approach significantly improves NV center performance for nanoscale sensing.
• The demonstrated sensitivity and imaging capabilities are unprecedented for scanning NV centers.