Actively tunable slow light in a terahertz hybrid metal-graphene metamaterial

TL;DR

This paper demonstrates a method to actively tune slow light in a terahertz hybrid metal-graphene metamaterial by modulating near field coupling through graphene's Fermi level adjustments, enabling dynamic control of phase dispersion.

Contribution

It introduces a novel actively tunable slow light device in the THz regime using a hybrid metal-graphene metamaterial with controllable near field coupling.

Findings

Achieved active modulation of slow light via Fermi level tuning.

Demonstrated dynamic control of phase dispersion in the metamaterial.

Proposed a compact design for THz slow light devices.

Abstract

We theoretically and numerically demonstrate an actively tunable slow light in a hybrid metal-graphene metamaterial in the terahertz (THz) regime. In the unit cell, the near field coupling between the metallic elements including the bright cut wire resonator and the dark double split-ring resonator gives rises to a pronounced transmission peak. By positioning a monolayer graphene under the dark mode resonator, an active modulation of the near field coupling is achieved via shifting the Fermi level of graphene. The physical origin can be attributed to the variation in the damping rate of the dark mode resonator arising from the conductive effect of graphene. Accompanied with the actively tunable near filed coupling effect is the dynamically controllable phase dispersion, allowing for the highly tunable slow light effect. This work offers an alternative way to design compact slow light devices in the THz regime for future optical signal processing applications.