Abstract-Graphene terahertz modulators by ionic liquid gating

Yang Wu, Chan La-o-vorakiat, Xuepeng Qiu, Jingbo Liu, Praveen Deorani, Karan Banerjee, Jaesung Son, Yuanfu Chen, Elbert E. M. Chia, Hyunsoo Yang

http://xxx.tau.ac.il/abs/1506.02363

(Submitted on 8 Jun 2015)

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.