Broadband terahertz modulators using self-gated graphene capacitors

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2015-09-01
Kakenov, Nurbek
Balci, Osman
Polat, Emre O.
Altan, Hakan
KOCABAŞ, COŞKUN
We demonstrate a terahertz intensity modulator using a graphene supercapacitor which consists of two large-area graphene electrodes and an electrolyte medium. The mutual electrolyte gating between the graphene electrodes provides very efficient electrostatic doping with Fermi energies of 1 eV and a charge density of 8 x 10(13) cm(-2). We show that the graphene supercapacitor yields more than 50% modulation between 0.1 and 1.4 THz with operation voltages less than 3 V. The low insertion losses, high modulation depth over a broad spectrum, and the simplicity of the device structure are the key attributes of graphene supercapacitors for THz applications. (C) 2015 Optical Society of America