Cover story: Li H, Zhao CH, Li J et al. Spindependent amplitude and phase modulation with multifold interferences via single-layer diatomic all-silicon metasurfaces. Opto-Electron Sci 4, 240025 (2025).

The diatomic metasurface achieves amplitude and phase modulation by leveraging the interferometric superposition of the fields scattered by two distinct resonators. These two resonators interact with the incident light and generate scattered fields that interfere constructively or destructively depending on their relative amplitudes and phases. This mechanism offers high flexibility and efficiency for wavefront control, making it an attractive solution for advanced photonic applications. Spin-selective transmission was accomplished by utilizing a pair of all-silicon meta-atoms that maintained a constant phase difference. The distinct modulation functions arise from geometric phase profiles characterized by multiple rotational properties, which introduce independent parametric factors that elucidate their physical significance. A series of THz metasurface samples with specific modulation functions are characterized, experimentally demonstrating the accuracy of ondemand manipulation. Central to this innovation is the interference effect with multiple rotational features, which ensures that spin-selective transmission occurs and enables robust control of amplitude and phase in a manner analogous to integrated optoelectronic devices. In the scientific landscape, the proposed design strategy achieves dual modulation in a single layer of metasurface without requiring bulky or multilayered optical elements. Applicable to reflection, transmission, or polarization-dependent metasurfaces, enhancing their functionality for holography, beam shaping, and wavefront engineering.