3-D Metamaterial Based Terahertz Planoconcave Lenses for Linearly and Circularly Polarized Waves

作     者：Marishwari, Muthusamy Subramanian, Venkatachalam Ouyang, Zhengbiao Yogesh, Natesan 

作者机构： Chennai600025 India Microwave Laboratory Department of Physics Indian Institute of Technology Madras Chennai600036 India THz Technical Research Center of Shenzhen University Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen518060 China Department of Physics National Institute of Technology Calicut Kerala Kozhikode673601 India 

出 版 物：《Progress In Electromagnetics Research B》 (Prog. Electromagn. Res. B)

年 卷 期：2023年第98卷

页      面：21-37页

核心收录：

学科分类：080805[工学-电工理论与新技术] 080904[工学-电磁场与微波技术] 0808[工学-电气工程] 070207[理学-光学] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：This work was carried out based on the facilities funded by the Department of Science and Technology  Ministry of Science and Technology  India (DST/INSPIRE/04/2015/002420) 

主　　题：Metamaterials 

摘      要：A three-dimensional negative index (NI) metamaterial (MTM) is realized at terahertz (THz) frequencies. The structure is composed of orthogonally oriented cross-bars with arrows on each corner embedded in a dielectric cube. The proposed 3-D MTM is symmetric along all the principal axes and shows a polarization-insensitive, wide-incident-angle negative refractive index regime centered at 0.862 THz with an operational bandwidth of 0.234 THz (27.15%). Using staircase approximation, the proposed 3-D NI MTM has been designed into a THz parabolic planoconcave lens (PCL). A PCL made of a NI medium is a counterpart of a positive index planoconvex lens and focuses on the nearfield region. The designed PCL shows 3-D focusing functionality for linearly and circularly polarized THz waves at 0.85 THz. The designed PCL has a short focal length and high numerical aperture (NA) with sub-wavelength focusing spot sizes. The computed FWHMs along transversal directions are 0.46A(x) x 0.49A(y) for transverse electric (TE) polarized wave, 0.46A(x) x 0.49A(y) for left-circularly polarized (LCP) wave, and 0.50A(x) x 0.42A(y) for right-circularly polarized (RCP) wave, respectively. The corresponding back focal lengths of the realized PCLs are 1.07A, 1.03A, and 0.98A, and the focal depths are 0.40A, 0.48A, and 0.41A for linear, LCP, and RCP waves, respectively. A short review of recent progress in manufacturing techniques for the fabrication of the proposed 3-D MTM is further highlighted. Since the proposed 3-D MTM PCL configurations show the far-field focusing of linearly/circularly polarized waves, imaging with high optical power requirements can be met for THz waveband applications. © (2023), (Electromagnetics Academy). All Rights Reserved.