Light-narrowed optically pumped Mx magnetometer with a miniaturized Cs cell

We demonstrate a way of operating an optically pumped magnetometer with miniaturized cesium cell using the light-narrowing effect. The magnetometer setup shows improvement of shot-noise-limited sensitivity (42 fT/root Hz in a cell of only 9.3 mm(3) volume) due to the suppression of spin-exchange relaxation to a large extent and the use of a strikingly increased fraction of alkali-metal atoms for signal generation, working even in mu T magnetic fields, by using only a single high-intensity laser beam both for pumping and probing of atomic spins.