Dynamically tunable plasmonically induced transparency in periodically patterned graphene nanostrips

We present a dynamically wavelength tunable plasmonically induced transparency (PIT) planar device composed of periodically patterned graphene nanostrips for the mid-infrared region. The PIT effect can be achieved by a single layer of graphene nanostrips for a fixed Fermi energy. The PIT resonant wavelength can be dynamically tuned while maintaining PIT modulation strength, transmission peaks, and spectral line width by varying the Fermi energy of graphene without re-optimizing and re-fabricating the nanostructures. A three-level plasmonic system is demonstrated to well explain the formation mechanism of the wavelength tunable PIT in the graphene nanostrips. This work may offer a further step in the development of a compact tunable PIT device.