Plasmonic Magnetic Sensor Based on Graphene Mounted on a Magneto-Optic Grating

In this paper, we propose a magnetic sensor utilizing the non-reciprocal propagation of surface plasmons (SPs) on a graphene layer mounted on a magneto-optic grating. An incident electromagnetic wave upon the graphene layer can be absorbed and, under certain conditions, coupled to the SPs along the layer. The sensor structure is assumed to be parallel to the applied magnetic field, the parameter which should be sensed and measured. Contrary to the case with no magnetic field bias and due to magneto-optic characteristics of the grating substrate, wave absorbance for each incident mode can be realized in two different frequencies with non-reciprocal behavior. The frequency difference between these distinct modes depends on the applied magnetic field. This idea can provide a proper approach to sense and measure the magnitude of the applied magnetic field. The performance of the proposed structure is studied analytically and confirmed by numerical simulations. The sensor can be utilized extensively in various systems employing the magnetic field capabilities such as medical diagnostic devices and physicists' experimental setups.