A Fiber-Coupled Scanning Magnetometer with Nitrogen-Vacancy Spins in a Diamond Nanobeam

Area of Science:

• Condensed Matter Physics
• Quantum Sensing
• Nanotechnology

Background:

• Nitrogen-vacancy (NV) spins in diamond are valuable for nanoscale magnetic imaging.
• Optical access for NV spin readout is a significant challenge in extreme environments like millikelvin cryostats and biological systems.

Purpose of the Study:

• To demonstrate a novel scanning-NV sensor overcoming traditional optical access limitations.
• To enable efficient optical excitation and readout of NV spins through an integrated optical fiber.

Main Methods:

• Fabrication of a diamond nanobeam sensor optically coupled to a tapered optical fiber.
• Utilizing through-fiber optical interrogation for electron spin resonance (ESR).
• Implementing proof-of-principle magnetometry by imaging spin waves in yttrium-iron-garnet (YIG) thin films.

Main Results:

• Successful demonstration of a scanning-NV sensor with high-efficiency through-fiber optical readout.
• Achieved optically interrogated ESR and magnetometry using the nanobeam sensor.
• Showcased imaging of spin waves in YIG thin films.

Conclusions:

• The developed scanning-nanobeam sensor provides a robust solution for NV-based magnetic imaging in challenging environments.
• Potential for integration with nanophotonics to enhance light-matter interactions.
• Opens new avenues for all-fiber sensor applications, particularly in millikelvin systems.