Figure 1. Illustration of plasma waves in graphene FETs for terahertz detection and modulation.

(a) The formation of plasmonic cavity with electric vibrator at top contact monitoring the conductivity of graphene channel, the bottom gate is used to tune the Fermi level, and the cascade cooperative plasma oscillation is formed, leading to the rectify and detection of THz radiation (seeing Materials and Methods). (b) The conical band structure and the optical process are shown. The plasmon enabled intraband electron transition is dominant due to the Pauli blocking and low density of states at Dirac point. (see Supplementary Information). (c) Left column: the proposed MGL-FETs with the stacked graphene sheets being connected to different or same voltage sources if needed, the grating contacts at the top side act both as electrodes and couplers. Right column: with an applied bias, the shift of Hartree band and the Fermi level accommodate the carriers' distributions.