Compact Metalens Design for Ultra-Wideband Achromatic Imaging in the Visible Spectrum

Abstract

This work presents a transformative advancement in planar optics through the design, fabrication, and characterization of an ultra-wideband achromatic metalens operating across the visible to near-infrared spectrum (400–1100 nm). By employing zone division multiplexing on a multilayer architecture with silicon nitride nanostructures, the proposed lens achieves an unprecedented numerical aperture of 0.9 and diameter of 20 mm, overcoming the fundamental dispersion limitations of conventional single-layer designs. Experimental validation demonstrates excellent agreement with simulations, revealing focusing efficiency exceeding 80% in the 780–820 nm range, near-diffraction-limited focal spots with 0.5 μm FWHM, and remarkable robustness against angular deviations up to ±20°. This integrated metalens platform offers promising solutions for high-precision imaging applications in microscopy, astronomy, and virtual reality systems.