A Holographic Broadband Achromatic Metalens

Abstract Metalens with nanostructured optical elements are designed to control wavefront shaping at the wavelength‐scale thickness. However, most metalens still suffer from large chromatic aberrations due to phase dispersion, limiting their wide applications for multiple wavelengths. Here, avoiding complex resonant designs or multiple‐layer nanostructures, a simple broadband achromatic metalens by holographic diffraction in the visible spectrum is demonstrated. The hyperbolic phase distributions of multiple discrete wavelengths within a shared aperture and fabricate a broadband achromatic diffractive metalens by flexible direct‐laser‐writing technique is randomly interleaved. The designed polarization‐insensitive metalens modulate the light field by changing the height of the artificial neuron phase units to achieve average focusing efficiencies of 55% in the visible spectrum. This holographic design concept can pave the way to expand achromatic metalenses to multiple spectra.