Utilising NV based quantum sensing for velocimetry at the nanoscale

Area of Science:

• Quantum sensing
• Nanoscale physics
• Fluid dynamics

Background:

• Nitrogen-Vacancy (NV) centers in diamond are advanced nanoscale magnetometers.
• NV centers can retrieve Nuclear Magnetic Resonance (NMR) spectra from low signal-to-noise ratio samples.
• Magnetic noise from diffusing particles and flowing liquids affects NV center coherence.

Purpose of the Study:

• To propose a non-intrusive method for measuring drift velocity near flow channel surfaces using NV center quantum sensing.
• To analyze the sensitivity of different measurement protocols for nanoscale velocimetry.
• To demonstrate the effectiveness of the proposed scheme, especially when diffusion noise is dominant.

Main Methods:

• Utilizing NV centers in diamond for magnetic field quantum sensing.
• Developing a non-intrusive setup to measure drift velocity in flow channels.
• Analyzing quantum sensor sensitivity and performance under dominant diffusion effects.

Main Results:

• A novel nanoscale velocimetry scheme based on NV center quantum sensing is proposed.
• The scheme provides detailed sensitivity analysis for various measurement protocols.
• The proposed method outperforms fluorescence-based approaches, even when diffusion noise is significant.

Conclusions:

• The NV-based nanoscale velocimetry scheme offers a powerful tool for microfluidic research.
• It enables accurate drift velocity measurements in low-flow regimes where properties are unclear.
• This advancement is crucial for developing future microfluidic and nanofluidic infrastructures.