Graphene terahertz modulators by ionic liquid gating

TL;DR

This paper demonstrates a highly efficient graphene-based terahertz modulator using ionic liquid gating, achieving up to 93% transmittance modulation across 0.1 to 2.5 THz at low voltage.

Contribution

It introduces a novel ionic liquid gating technique to tune graphene's Fermi level for terahertz modulation, achieving high modulation depth and stability.

Findings

Achieved up to 93% transmittance modulation in THz range.

Demonstrated stable and repeatable modulation at room temperature.

Operated effectively with only 3 V voltage.

Abstract

Graphene based THz modulators are promising due to the conical band structure and high carrier mobility of graphene. Here, we tune the Fermi level of graphene via electrical gating with the help of ionic liquid to control the THz transmittance. It is found that, in the THz range, both the absorbance and reflectance of the device increase proportionately to the available density of states due to intraband transitions. Compact, stable, and repeatable THz transmittance modulation up to 93% (or 99%) for a single (or stacked) device has been demonstrated in a broad frequency range from 0.1 to 2.5 THz, with an applied voltage of only 3 V at room temperature.