Dispersion-Contrasting Dual-Layer Metalens for Hybrid Chromatic-Aberration Correction in the Visible.

Metalenses offer a pathway toward flat, wafer-level optics, but their translation to mobile imaging has been hindered by the difficulty of achieving broadband performance at millimeter-scale apertures. Here we report a visible metalens that imparts a wavelength-invariant phase profile in a hybrid configuration with refractive elements. Central to this advance is a dispersion-contrasting metasurface that achieves broadband phase control using simple, photolithography-compatible nanostructures. Built from stacked silicon nitride nanohole and titanium dioxide nanopost arrays with opposite dispersion sensitivities, the device independently controls phase and group delay while maintaining high transmission across the visible. Integrated with refractive optics, it produces full-color photographic images free of visible artifacts under conditions representative of mobile camera modules. Interferometric measurements show that image quality is governed by phase fidelity of the metalens, demonstrating that accurate, manufacturable phase control provides a viable route toward integrating visible metalenses into compact imaging systems.