Performance limitations of active plasmonic devices based on magnetic field detuning of the surface plasmon-polariton resonance in subwavelength semiconductor wires

Abstract

Subwavelength plasmonic wires provide a very simple, ultracompact, and efficient platform for active plasmonics. We theoretically investigate magnetically switched transparency in subwavelength semiconductor wires. The main difficulty limiting the performance of magnetoplasmonic devices and subwavelength optical isolators is the need to use a strong magnetic field. We reveal that the required magnetic field intensity in subwavelength semiconductor wires is twice higher than that in planar semiconductor interfaces and is determined by the carrier mobility of the constituent semiconductor and does not directly depend on other material parameters such as the coating dielectric permittivity, the semiconductor carrier density, and the electron's effective mass. The azimuthal magnetic field can be excited by a direct electric current or by an optical pump through the semiconductor wires. Our finding points to the important limitations on the performance of active plasmonic devices based on magneto-optical transparency in the plasmonic wires.