Multi-Focus Imaging Utilizing Huygens Metasurface

Full control of electromagnetic (EM) wave is an important and tough issue for electromagnetism. Recently, Huygens metasurface is proposed to manipulate the propagation of EM wave with a relatively high efficiency. Huygens metasurface can be regarded as a two-dimensional array composed of crossed magnetic and electric dipoles which can generate specific electromagnetic response. By elaborately designing of these dipoles in each metaatom, the desired surface electric and magnetic current can be achieved. The surface current can manipulate the scattered electric and magnetic field distribution above and below the metasurface indirectly according to the boundary condition. Then, full manipulation of the amplitude and phase for the transmitted wave can be achieved with the variation of shape parameters. Based on the proposed transmission-type Huygens metaatoms, multi-focus imaging metalenses are realized by arranging each metaatom with the calculated transmission phase. Our design provides potential applications in microwave antenna and imaging systems.