Open AccessTunable perfect magnetic mirrors and retroreflectors in terahertz band
Author(s) -
Hao Song,
Lei Sun,
Guo Ping Wang
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.382965
Subject(s) - retroreflector , optics , terahertz radiation , metamaterial , grating , lithium tantalate , magnetic field , physics , reflector (photography) , magnetic dipole , ray , optoelectronics , materials science , lithium niobate , laser , light source , quantum mechanics
A magnetic mirror operating in the terahertz band is designed based on the functional reflective metasurface, which is simply constructed by a one-dimensional periodic lithium tantalate micro cylindrical rod array on a Teflon substrate coated with a metal layer at the bottom and reflects the incoming electric field with a zero-phase change. Magnetic dipole resonance of the micro cylindrical rods excited in the metasurface is attributed to the perfect magnetic mirror at the frequency of 0.286 THz with the reflectivity of R = 0.98 for a normal incident electromagnetic wave. By real-time varying the direction from normal (0) to 28.45 degrees and the frequency from 0.286 to 0.382 THz of the incident wave, the metasurface can still behave as a perfect magnetic mirror with the reflectivity as high as 0.99. Most interestingly, in this case, the metasurface possesses the property of a retroreflector that the reflected wave returns along the direction of the incident wave, which is consistent with the grating equation. The tunable perfect magnetic mirror effect and the retroreflector property may provide ways in novel photonic devices and sensing applications.