Fast magnetic field imaging using an optically pumped magnetometer readout by a high-speed camera

Abstract

We present a magnetometric imaging device that harnesses the sensitivity of free spin precession (FSP) optically pumped magnetometers alongside a high-speed camera. This approach enables the rapid imaging of magnetic field distributions at a frame rate of 120 Hz, achieving an intrinsic sensitivity of 111 pTHz and a spatial resolution of 280 μm, using a microfabricated rubidium (Rb87) vapor cell filled with nitrogen buffer gas to mitigate diffusion. Our device employs the parallel readout capability of the camera to effectively remove common-mode noise. The imaging capabilities were demonstrated by capturing the magnetic field distribution created by a defined current running through a pair of wires. Recording FSP signals using a commercial camera simplifies the experimental setup and allows for a larger number of pixels, paving the way for practical applications in industrial environments. Although FSP magnetometers exhibit lower sensitivity compared to their spin exchange relaxation free counterparts, they offer a broader tolerance to magnetic offset fields, making them suitable for deployment in less magnetically clean environments.