Multifocal flat lens using thin anisotropic surface in visible light spectrum

In this study, a novel design methodology of multifocal flat lens using a thin anisotropic surface is proposed and investigated in visible light spectrum. The unit cell of the anisotropic surface consists of two identical electric field coupled resonators (ELCRs) separated by a dielectric substrate. When the wave-front of transmitted wave through the anisotropic surface has a shape of parabola, the focusing spot can be generated at focal point. The transverse and longitudinal multi-focusing can be achieved by a separated mode and a chessboard alternating mode, respectively. The feasibility of the methodology is confirmed by both analytic and simulated results for circular polarization incidence with wavelength of 600 nm.