Terahertz multimode modulator based on tunable triple-plasmon-induced transparency in monolayer graphene metamaterials
Shanshan Zhuo, Fengqi Zhou, Yanli Liu, Zhimin Liu, Xiao Zhang, Xin Luo, Yipeng Qin, Guangxin Yang, Cheng Ji, Zizhuo Zhou, Liwen Sun, Ting Liu
Abstract
A simple monolayer graphene metamaterial based on silicon/silica substrates is proposed, and typical triple-plasmon-induced transparency (PIT) is realized in the terahertz band. The physical mechanism is analyzed by coupled mode theory (CMT), and the results of CMT agree well with the finite-difference time-domain simulation. A multimode electro-optical switch can be designed by dynamic tuning, and the modulation degrees of its resonant frequencies are 84.0%, 87.3%, 83.0%, 88.1%, and 76.7%. In addition, triple-PIT gradually degenerates into dual-PIT with a decrease in the length of one bright mode. Interestingly, the group index can reach 770 at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">E</mml:mi> <mml:mi mathvariant="normal">f</mml:mi> </mml:mrow> </mml:mrow> <mml:mo>=</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>0.8</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">e</mml:mi> <mml:mi mathvariant="normal">V</mml:mi> </mml:mrow> </mml:mrow> </mml:math> , which shows that it can be designed as a slow light device with extraordinary ability. Therefore, the results of this paper are of great significance to the research and design of electro-optical switches and slow light devices in the terahertz band.