Graphene-based tunable terahertz modulators

We report on terahertz amplitude modulators using electrolyte-gated graphene single layersplaced at a quarter wavelength distance from a reflecting Au film (Salisbury mirror scheme).By exploiting the electric field concentration at the graphene/electrolyte interface, a modulation as high as 45% is achieved in a wide spectral range (1.5-6 THz) with applied voltagesin the range [-0.6 V, +0.6 V], which is remarkable considering the small voltages and theatomically thin active region. Graphene-based THz modulators' main advantages are: facilefabrication, low cost and excellent tunability, thus promising for THz system applications.