Active Control and Large Group Delay in Graphene-Based Terahertz Metamaterials

Abstract

A distinct plasmon-induced transparency (PIT) window has been realized in our novel design of |+|-shaped graphene metamaterials, which consist of two identical graphene strips and a cross-shaped graphene resonator in the right middle. The two strips serve as the dark resonator, and the cross-shaped graphene plays the bright one. Active control of the PIT window can be modulated from the on state to the off state only by breaking structure symmetry. Furthermore, the PIT window can be dynamically adjusted with different Fermi energies in a non-contact way. More importantly, the proposed metamaterial structure achieves a maximum group delay of 13.28 ps, which is much higher than that in the previous paper. In the case of sensing application, the position of the PIT window has been investigated with different embedded media, and it shows a linear function of the refraction index. This study may open up new avenues for the development of highly integrated optical filters, optical sensors, or integrated optical switches.