Ultra-high consistency multichannel SERF atomic magnetometer based on diffractive optics.

Multichannel spin-exchange relaxation-free (SERF) atomic magnetometers (AMs) have broad application prospects in array biomagnetic measurement systems because of their high spatial resolution. This study proposed an efficient and high-quality beam-splitting method based on a diffractive optical element (DOE), which enables multichannel SERF AM to maintain ultrahigh consistency with a channel interval of 3.27 mm. Based on the relaxation rate model under zero-field resonance, the minor differences in the magnetic linewidth of each channel were analyzed. The experimental results demonstrated ultra-high consistency of the magnetic field measurement signals between multiple channels, with a nonlinear error of less than 0.1%. The optimal sensitivity for a single channel was 11.9 fT/Hz 1 / 2 @31.5 Hz, and 9.3 fT/Hz 1 / 2 @31.5 Hz in the first-order gradiometer mode. The structure also satisfied the requirements of long-term high stability and high sensitivity, which are expected to further obtain more measurement channels. This method plays a critical role in improving the accuracy of magnetocardiography (MCG) and magnetoencephalography (MEG) systems. [Display omitted] • Implemented a highly consistent method of beam splitting in a magnetometer. • The distance between channels of the multichannel atomic magnetometer is 3.27 mm. • After beam splitting, the nonlinear error of each channel is less than 0.1%. • The sensitivity of a single channel is 11.9 fT/Hz 1 / 2 @31.5 Hz. • The sensitivity can reach 9.3 fT/Hz 1 / 2 @31.5 Hz in a first-order gradiometer mode. [ABSTRACT FROM AUTHOR]