Tunable plasmon induced transparency and multispectral transparency with large group delay in graphene metamaterials

摘要

Tunable plasmon included transparency (PIT) and multispectral transparency in the THz region have been achieved with graphene metamaterials, which consist of four graphene cut wires on the dielectric substrate. The PIT transparency window originates from the bright-bright mode coupling with two sets of identical graphene stips. The electric field distribution at each resonant peak is fully examined and the number of optical resonant peaks can be flexibly altered with the designed strip length. The transmission spectra agree well with the Lorentz fitting. Moreover, multispectral transparency can also be dynamically tuned via Fermi energy (E-F). Namely, the resonant peaks move into the high frequency region with a larger E-F. The dispersion behavior is explored elaborately and the group delay can reach up to 10.22 ps, which is one magnitude higher than the previous work. Finally, the movement of the multispectral transparency with different embedded solutions is fully examined in the application of sensing. Such active and switchable graphene metamaterials may open up a new avenue in the application of optical filters, switchers or sensors.