Exceptional Point-Driven Multi-Channel Electron Spin Polarization

Atomic magnetometers (AMs) are among the most promising platforms for ultrasensitive magnetic field detection, achieving femtotesla-level sensitivity in compact, portable architectures. Multichannel magnetic-field measurements within a single vapor cell are intrinsically limited by nonuniform optical pumping, which leads to inconsistent channel responses and degraded spatial resolution. Here, we introduce a novel planar antenna approach based on exceptional-point (EP) that generates an intrinsically uniform, strongly confined radiation field resonant with the 87 Rb D1 transition. By exploiting the non-Hermitian modal dynamics near EPs in the antenna bandstructure, specifically engineered silicon nitride antennas generate spatially uniform and confined optical fields, enabling submillimeter-resolution optical pumping within a miniature vapor cell. In particular, simulations demonstrate that rectangular-etched and laterally homogeneous dielectric antennas reduce the interchannel nonuniformity by nearly an order of magnitude, relative to conventional Gaussian pumping. This method combines the unique physics of EPs with the scalability of planar photonics, potentially offering a new route toward compact, high-spatial-resolution atomic sensor arrays and highlighting the potential for future integrated photonic platforms for precise, multichannel magnetic signal readout.