Zero field optically pumped magnetometer with independent dual-mode operation

We propose a dual-mode optically pumped magnetometer (OPM) that can flexibly switch between single-beam modulation mode and double-beam DC mode. Based on 4 mm×4 mm miniaturized vapor cell, the achieves sensitivity of 7 fT/Hz1/2 with probe noise below working bandwidth over 65 Hz. This is designed to precisely measure floor mu-metal magnetic shield. The (sensitivity 20 fT/Hz1/2) exhibits characteristics suitable for biomagnetic measurements. Thus, our design OPM multiple functions, including magnetic-shield background measurement medical imaging.