EQUS researchers have proposed a high-sensitivity magnetometry scheme based on a diamond Raman laser with visible pump absorption by nitrogen-vacancy centres in the same diamond crystal.

Magnetic-field sensing is important in many industries. One proposal for precision sensing is visible-wavelength laser threshold magnetometry. The original proposal for this is based on a continuous-wave diamond nitrogen–vacancy spin laser, but has yet to be realised experimentally.

The EQUS team investigated laser threshold magnetometry instead using the well-established visiblewavelength diamond-crystal Raman laser, which makes it more experimentally plausible. They proposed a conceptually simple and highly sensitive room-temperature quantum magnetic sensor that combines a diamond-crystal Raman laser and nitrogenvacancy defect spins in the same crystal. The magnetic field is sensed by looking at the output from the Raman laser, which varies because of the magnetic-field-dependent optical absorption of the laser’s pump by nitrogen–vacancy spins.

Their results show the experimental feasibility of the magnetic sensor for room-temperature applications such as mineral exploration and navigation. The next step is to realise the idea experimentally, enabling the team to explore the sensing capabilities of a chip-scale diamond Raman laser.

Published in the 2021 EQUS Annual Report. Written by Kristen Harley.