Scanning localized magnetic fields in a microfluidic device with a single nitrogen vacancy center

TL;DR

This paper demonstrates a method for localized magnetic field measurement in a microfluidic device using a single nitrogen vacancy center in diamond, achieving nanometer spatial precision and high magnetic sensitivity.

Contribution

It introduces a novel approach combining microfluidic control and NV center magnetometry for 3D magnetic field mapping at nanometer resolution.

Findings

Achieved 48 nm magnetic particle position control.

Attained 17.5 μT/Hz^1/2 magnetic field sensitivity.

Enabled local magnetic property studies in biological systems.

Abstract

Nitrogen vacancy (NV) color centers in diamond have emerged as highly versatile optical emitters that exhibit room temperature spin properties. These characteristics make NV centers ideal for magnetometry, which plays an important role in chemical and biological sensing applications. The integration of NV magnetometers with microfluidic systems could enable the study of isolated chemical and biological samples in a fluid environment with high spatial resolution. Here we demonstrate a method to perform localized magnetometry with nanometer spatial precision using a single NV center in a microfluidic device. We manipulate a magnetic particle within a liquid environment using a combination of planar microfluidic flow control and vertical magnetic actuation to achieve 3-dimensional manipulation. A diamond nanocrystal containing a single NV center is deposited in the microfluidic channels and acts as a local magnetic field probe. We map out the magnetic field distribution of the magnetic particle by varying its position relative to the diamond nanocrystal and performing optically resolved electron spin resonance (ESR) measurements. We control the magnetic particle position with a 48 nm precision and attain a magnetic field sensitivity of 17.5 microTesla/Hz^1/2. These results open up the possibility for studying local magnetic properties of biological and chemical systems with high sensitivity in an integrated microfluidic platform.