Achieving a High Q-Factor and Tunable Slow-Light via Classical Electromagnetically Induced Transparency (Cl-EIT) in Metamaterials

作者：Vafapour Z^*; Alaei H

来源：Plasmonics, 2017, 12(2): 479-488.

DOI：10.1007/s11468-016-0288-0

• Classical-EIT
• Group Index
• Plasmonic Sensing
• Optical switching
• Slow-light devices

We report on our numerical work concerning a 3D planar nano-structure metamaterial exhibiting classical electromagnetically induced transparency (Cl-EIT). The interaction between two different plasmonic modes of the unit cell, induced directly or indirectly by the incident electromagnetic wave, leads to a transparent window, resembling the Cl-EIT. Their interactions and coupling between plasmonic modes are investigated in detail by analyzing magnetic field distributions and spectral responses. Simply by introducing of symmetry broken of the proposed nano-structure, the Cl-EIT can be dynamically tuned. At one special asymmetric case, a sharp transparency window with the bandwidth of about 2.96 nm (corresponding to 0.6 THz in frequency regime) is obtained at 246.3 THz (corresponding to 1.218 mu m). The corresponding quality factor (Q-factor) is 411. Also, we show that the Cl-EIT frequency position depended very sensitively on the used metal in the metamaterial. Furthermore, we demonstrate numerically that tunable slow light can be realized in our planar nano-structure metamaterial with the unit cell composed of dark and bright plasmonic modes in a broad terahertz regime. It is demonstrated that the increased Q-factor leads to large group index (of the order of 620), which is promising for efficient plasmonic sensing, optical switching, and slow-light devices design.

• 出版日期2017-4