title: Planar holographic metasurfaces for terahertz focusing.
abstract: Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can be miniaturized and designed with additional functionalities, holding promise for system integration. To demonstrate this potential, here ultrathin reflection metasurfaces (also called metamirrors) designed for focusing terahertz radiation into a single spot and four spaced spots are proposed and experimentally investigated at the frequency of 0.35 THz. Each metasurface is designed using a computer-generated spatial distribution of the reflection phase. The phase variation within 360 deg is achieved via a topological morphing of the metasurface pattern from metallic patches to U-shaped and split-ring resonator elements, whose spectral response is derived from full-wave electromagnetic simulations. The proposed approach demonstrates a high-performance solution for creating low-cost and lightweight beam-shaping and beam-focusing devices for the terahertz band.
authors.affiliation: 1] Novosibirsk State University, Pirogova St. 2, Novosibirsk, 630090, Russian Federation [2] Budker Institute of Nuclear Physics SB RAS, Lavrentiev Ave. 11, Novosibirsk, 630090, Russian Federation [3] Institute of Semiconductor Physics SB RAS, Novosibirsk Branch "TDIAM", Lavrentiev Ave. 2/1, Novosibirsk, 630090, Russian Federation.
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Kuznetsov
authors.affiliation: 1] Novosibirsk State University, Pirogova St. 2, Novosibirsk, 630090, Russian Federation [2] Budker Institute of Nuclear Physics SB RAS, Lavrentiev Ave. 11, Novosibirsk, 630090, Russian Federation.
authors.forename: Mikhail A
authors.initials: MA
authors.lastname: Astafev
authors.affiliation: Antennas Group - TERALAB, Universidad Pública de Navarra, 31006, Pamplona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Beruete
authors.affiliation: 1] Optical and Semiconductor Devices Group, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2BT, London, UK [2] Centre for Plasmonics and Metamaterials, Imperial College London, London SW7 2AZ, United Kingdom [3] Centre for Terahertz Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Miguel
authors.initials: M
authors.lastname: Navarro-Cía