High-Throughput Fabrication of Curved Plasmonic Metasurfaces for Switchable Beam Focusing and Thermal Infrared Cloaking

Considerable effort is devoted to research on reconfigurable beam focusing and optical cloaking in the basis of metamaterials/metasurfaces. However, it remains a great challenge to achieve multifunctional wavefront control on curved platforms, especially in the reflective case, which is of paramount importance in the emerging fields of active optics and stealth research. This study proposes a novel strategy to control the versatile reflective structured wavefront on a conformal platform by curving a flexible metasurface. This metasurface is fabricated in a high-throughput manner by using ultra-violet nano-imprinting lithography (UV-NIL), and its efficacy is verified through consistent simulated and experimental results. The conformal metasurface is designed to realize multifunctional performance by employing all-metallic plasmonic structures based on the Pancharatnam-Berry (PB) phase. A general theoretical scheme is also proposed for the projection of a curved surface onto a reference plane by a judicious compensation, combining the geometrical PB phase with curvature-induced propagation phase. Moreover, as a proof-of-concept, curved metasurfaces with cylindrical shapes are experimentally characterized by their multifunctionalities in generating a beam spot with a continuously tunable focal length and reflecting plane waves used for camouflage, thereby confirming the feasibility and effectiveness of the proposed strategy.