Dual-wavelength diffraction-order-multiplexed metasurface for wide-angle sun sensing

Conventional pinhole-based sun sensors are fundamentally limited by the inherent trade-off between field of view (FOV) and angular resolution. To overcome this limitation, we propose a diffraction-order-multiplexed metasurface (DOMM). The DOMM consists of a periodic supercell array comprising 4 × 4 rectangular nanopillars that are optimized by a genetic algorithm and focuses two wavelengths while suppressing others. This architecture effectively redirects large-angle incident light onto a CMOS sensor, thereby extending the FOV from ±9.9° to ±40° without compromising angular resolution. The two wavelength channels provide mutual positional constraints, enabling unambiguous identification of diffraction orders and precise retrieval of incident angles. Simulations demonstrate an angular resolution better than 0.007° (3σ) over the entire FOV, offering a compact, robust solution for spaceborne sun sensors.