All-dielectric achromatic hole-array metasurfaces

Abstract

Metalens, an ultra-thin optical element composed of subwavelength structure, offers a new path for the development of miniaturized device imaging. Through the design of subwavelength units, arbitrary modulation of the phase, amplitude, and polarization of electromagnetic waves can be achieved. However, current metalenses generally suffer from the disadvantages of narrowband and Ohmic losses, which limits the development of high-quality imaging. In this work, using all-dielectric hole-array structure within the framework of effective medium theory, we demonstrate the achromatic focusing effect based on the basic Huygens principle. Moreover, by changing the position of the point source, this metalens can also achieve directional refraction with flexible angles. Our results provide a new solution for the practical application of miniaturized integrated high-quality imaging, and may open up avenues for constructing efficient artificial metasurface with metamaterials for energy harvesting and other wave manipulation.