All-dielectric high-NA achromatic metalenses in the mid-infrared band based on subregions

For conventional refractive lenses, chromatic aberration inevitably occurs due to the refractive index variation of the lens material with the incident wavelength, leading to axial aberrations and lower imaging system quality. Achromatic metalenses have demonstrated a great capability to solve this problem and been extensively investigated. However, the metalens achromatic method involves construction of a unit structure satisfying a phase distribution greater than 0-2