Magnetic field imaging with an optical microscope using a quantum diamond sensor add-on

TL;DR

This paper presents an add-on for standard optical microscopes that enables magnetic field imaging using nitrogen-vacancy diamond sensors, combining traditional optical modes with quantum magnetic sensing for versatile, cost-effective microscopic magnetic studies.

Contribution

The authors developed a retrofit module for existing microscopes that integrates NV-diamond sensors, allowing magnetic imaging without specialized equipment, expanding accessibility and functionality.

Findings

Successful imaging of magnetic particles using multiple modes

Rapid iso-magnetic field visualization within seconds

Demonstration of three-dimensional stray field imaging

Abstract

Widefield magnetic imaging using ensembles of nitrogen-vacancy (NV) centres in diamond has emerged as a useful technique for studying the microscopic magnetic properties of materials. Thus far, this technique has mainly been implemented on custom-made optical microscopes. We have developed an add-on for a standard laboratory optical microscope that integrates the NV-diamond sensor and necessary light source, microwave antenna, and bias magnet, enabling NV-based magnetic imaging while retaining the typical optical measurements modes of the microscope. We demonstrate our retrofitted quantum diamond microscope by imaging a magnetic particle sample using brightfield, darkfield, and magnetic imaging modes. Furthermore, we employ an iso-magnetic field imaging technique to visualise the magnetic field of the sample within seconds, and finally demonstrate three-dimensional stray field imaging. Retrofitting existing microscopes exploits the stability and high quality of traditional optical microscope systems while reducing the cost and space requirements of establishing a standalone magnetic imaging system.