Metasurface Based Crosstalk Reduction in Miniaturized Multi-Channel Optical Magnetometers

We present a metasurface-based approach to reduce crosstalk in single-cell multi-channel optical magnetometers, which is critical for achieving high spatial resolution. A theoretical model reveals that minimizing pump beam intensity at channel edges effectively suppresses crosstalk caused by atomic diffusion. Based on this, an imaging metasurface is designed using the Gerchberg-Saxton algorithm to split a single beam into multiple spots, each defining an independent measurement channel. The metasurface, fabricated with subwavelength amorphous silicon pillars, offers high transmittance and polarization insensitivity, and is compatible with on-chip integration. Numerical simulations validate the beam-splitting performance and demonstrate the flexibility of the metasurface to generate various spot profiles, meeting diverse application requirements. This work provides a promising pathway toward compact, portable, and wearable biomagnetic sensing devices.