An achromatic metalens in the near-infrared region with an array based on a single nano-rod unit

Abstract

Metasurfaces which encompass nanoantenna arrays in ultra-thin layers exhibit great application potentials in versatile areas for example imaging, displays, optical holograms, polarizers, complex optical field manipulations and so on. Different from previous achromatic designs based on integrated-resonant unit elements, an ultra-simple configuration of a near-infrared achromatic metalens with an array based on a single antenna element is proposed and demonstrated with a numerical aperture = 0.3 in the wavelength range from 1 to 1.2 μm. The achromatic property with the perfect overlap of the focal points in the near-infrared region opens an avenue for innovative flat and low-cost near-infrared optical components.