Wave manipulation with metasurface lens in the cassegrain system

Abstract

As opposed to the conventional Cassegrain reflector, we introduce the metasurface lens into the design of the Cassegrain system as the primary component with the combination of a secondary metamirror. The electromagnetic fields reflected by the secondary metamirror would directly transmit through the metasurface lens, thus can remove the blockage effects from the secondary metamirror and generate well collimated beams with very low sidelobes compared with the traditional Cassegrain reflector. Especially, such a metasurface Cassegrain system also demonstrates the perfect capabilities of synthesizing the steerable beams and splitting beams when the metasurface lens is equipped with properly prescribed phase distributions. Finally, we fabricate the proposed metasurface lens based Cassegrain system and experimentally demonstrate the functionalities of generating highly directive radiations with beam scanning and beam splitting.