Ultrasensitive terahertz/infrared waveguide modulators based on multilayer graphene metamaterials

This paper studies and classifies the electromagnetic regimes of multilayer graphene-dielectric artificial metamaterials in the terahertz/infrared range. The employment of such composites for waveguide-integrated modulators is analysed and three examples of novel tunable devices are presented. The first one is a modulator with excellent ON-state transmission and very high modulation depth: >38dB at 70meV graphene's electrochemical potential (Fermi energy) change. The second one is a modulator with extreme sensitivity towards graphene's Fermi energy - a minute 1meV variation of the latter leads to >13.2dB modulation depth. The third one is a tunable waveguide-based passband filter. The narrow-band cut-off conditions around the ON-state allow the latter to shift its central frequency by 1.25% per every meV graphene's Fermi energy change.