Metasurface‐integrated atomic magnetometer using single‐frequency dual beams

Quantum sensing is rapidly advancing, creating new opportunities in fields such as fundamental science and advanced manufacturing. The optically pumped atomic magnetometer (OPM), known for its high sensitivity and compact form factor, has become a promising candidate for a range of applications. However, traditional OPM systems relying on bulky optical components and phase accumulation often face limitations in modulation precision and miniaturization. In this study, we introduce a miniaturized OPM design that incorporates a polarized metasurface and uses a single laser source for both pumping and detection. The polarized metasurface enables the transformation of linearly polarized light with arbitrary polarization azimuths into circularly polarized light, allowing for subwavelength-scale optical field manipulation and integrated beam splitting. In the developed system, both the circularly polarized pump beam and the zeroth-order linearly polarized probe beam are generated from the same metasurface device, forming a dual-path magnetometer architecture. This design significantly reduces the optical system size while achieving a sensitivity of 4.91 pT/Hz^1/2 in the 2-10 Hz frequency range, exceeding the performance of conventional dual-beam OPMs with comparable configurations. Experimental results demonstrate that the proposed OPM effectively utilizes the metasurface's optical properties to balance high sensitivity and system miniaturization. This work offers a practical approach for the integrated design of compact quantum sensing systems.