Magnetic field control of plasmon polaritons in graphene-covered gyrotropic planar waveguide

In this Letter, we report about magnetic field switching of plasmon polaritons propagating into a planar gyrotropic waveguide covered by two graphene layers at a deeply subwavelength scale. It is shown that applying an external magnetic field may lead to energy redistribution between two waveguide surfaces. The effect value resonantly depends on the relation between waveguide size and exciting light wavelength. A change in chemical potential of graphene layers may be used for tuning the phase shift between plasmon polaritons at near-resonant wavelengths. Evident effect may be observed at low magnetic fields (less than one tesla) for wavelengths about microns on a scale of tens of nanometers. Such an effect may be used for plasmonics, photonics. and optoelectronics devices, as well as sensing applications.