A Terahertz Modulator Based on Graphene Plasmonic Waveguide

Graphene has many novel properties such as the ability of guiding plasmonic wave at terahertz (THz) frequencies, chemical potential shift as the carrier density changed. Since carrier density of graphene can be modified by bias voltage, the coupling coefficients or propagation loss of graphene plasmon can be modulated easily. A compact wideband terahertz modulator is proposed to modulate and guide plasmonic waves. The surface plasmon polariton (SPP) propagation and the modulation depth in the graphene biased structure are numerically investigated. The proposed THz plasmonic modulator has a wide working band about 1 THz and its modulation depth reaches about 76% at the frequency of 8 THz, which have potential application in THz communication.