Zero-field remote detection of NMR with a microfabricated atomic magnetometer

Abstract

We demonstrate remote detection of nuclear magnetic resonance (NMR) with a microfabricated atomic magnetometer and microfluidic channel integrated on a single device. Detection occurs at zero magnetic field, which allows operation of the magnetometer in the spin-exchange relaxation free (SERF) regime and increases the proximity of sensor and sample by eliminating the need for a solenoid to create a leading field. We achieve NMR linewidths of 31 Hz, limited by residence time in the encoding region. In a fully optimized system, we estimate that, for 1 second of integration, 7 X 10¹³ protons in a volume of 1 mm³, prepolarized in a 10 kG field can be detected with a signal-to-noise ratio of about β.