FOCUSING FIELD SIMULATION OF METALENS BASED ON FDTD

As one of the most basic optical elements, lens is the crucial content in the courses of basic optics and information optics. However, due to the limitation of class hours and other reasons, the introduction of lens in the existing optics courses is limited to geometric lens. With the development of micro-nano optics, metalenses composed of sub-wavelength structures have been widely studied and applied due to their unique properties. To this end, introducing the frontier knowledge of metalens development into the optics course is beneficial to stimulate the students' interest to study and explore the mysteries of micro-nano optics, and thus make positive contributions to promoting the integration of teaching and research. In this paper, taking the optical design of a polarization-insensitive metalens as an example, we investigate the light propagation of that a plane waves passes through the metalens and show the focusing field distribution based on FDTD method. First, full-wave simulations of cylindrical sub-wavelength gratings with different diameters are carried out to obtain the phase information. With the phase values, the nanopillars are selected as the structure cells of the metalens, and are arranged to achieve the whole metalens according to the phase distribution of the ideal focusing. Further, the light field distributions of that a plane wave passes through the metalens are obtained by FDTD method. Finally, the focusing field distributions are analyzed and summarized.