Tunable terahertz reflection of graphene via ionic liquid gating

TL;DR

This paper demonstrates a highly efficient, room-temperature, tunable terahertz reflector using graphene and ionic liquid gating, with significant reflectance modulation across a broad spectral range.

Contribution

It introduces a simple, effective method to modulate graphene's THz reflectance via ionic liquid gating, expanding potential applications in THz optical components.

Findings

Reflectance modulated from 0.79% to 33.4%

Effective across 0.1 - 1.5 THz range

Room temperature operation

Abstract

We report a highly efficient tunable THz reflector in graphene. By applying a small gate voltage (up to 3 V), the reflectance of graphene is modulated from a minimum of 0.79% to a maximum of 33.4% using graphene/ionic liquid structures at room temperature, and the reflection tuning is uniform within a wide spectral range (0.1 - 1.5 THz). Our observation is explained by the Drude model, which describes the THz wave-induced intraband transition in graphene. This tunable reflectance of graphene may contribute to broadband THz mirrors, deformable THz mirrors, variable THz beam splitters and other optical components.