Open AccessDemonstration of group delay above 40 ps at terahertz plasmon-induced transparency windows
Author(s) -
Zhenyu Zhao,
Hui Zhao,
Rajour Tanyi Ako,
Jianbing Zhang,
Hongwei Zhao,
Sharath Sriram
Publication year - 2019
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.27.026459
Subject(s) - terahertz radiation , optics , materials science , metamaterial , plasmon , terahertz spectroscopy and technology , slow light , group delay and phase delay , localized surface plasmon , surface plasmon , radius , optoelectronics , physics , filter (signal processing) , photonic crystal , computer science , computer vision , computer security
Herein, we demonstrate one of the highest terahertz group delay of 42.4 ps achieved experimentally at 0.23 THz, on a flexible planar metamaterial. The unit cell of metasurface is made up of a textured closed cavity and another experimentally concentric metallic arc. By tuning the central angle of the metallic arc, its intrinsic dipolar mode is in destructive interference with the spoof localized surface plasmon (SLSP) on textured closed cavity, which results in a plasmon-induced transparency phenomenon. The measured transmittances of as-fabricated samples using terahertz-time domain spectroscopy validate numerical results using extended coupled Lorentz oscillator model. It is found that the coupling coefficient and damping ratio of SLSP relies on the radius of the ring structure of textured closed cavity. As a consequence, the slow light maximum values become manoeuverable in strength at certain frequencies of induced transparency windows. To the best of our knowledge, our experimental result is currently the highest value demonstrated so far within metasurface at terahertz band.