Enhanced absorptivity based on nonreciprocal effect of CdTe and excitation of surface polaritons

Abstract

In this work, the purpose of increasing the magneto-optical conversion rate is achieved by enhancing the electromagnetic field in the magnetic medium, thereby forcing the magneto-optical effect of the system by the excitation of magnetic or surface polaritons, which requires constructing a magneto-plasmon micro/nanoscale structure reasonably. Considering the current high absorptivity of non-reciprocal absorbers are almost at very small wavelengths, therefore, an one-dimensional periodic magnetic plasma crystal structure composed of gold film and diluted magnetic semiconductor was constructed for broading the absorption range, and the absorption efficiency and nonreciprocal effect were investigated based on the finite difference time domain method. Moreover, the geometrical parameters of crystal structure was systematically optimized due to the balance between magneto-optic effect and optical properties can be obtained by adjusting the geometric parameters of the structures, and high absorptivity and relative obvious nonreciprocal effect in mid-infrared band had been obtained. From the results, it can be showed that the emergence of absorptance resonance peaks and troughs mainly depends on the excitation of surface plasmon resonance and the symmetry of micro-cavity effect in grating grooves. The achievement in this work provides new ideas for the study of nonreciprocal optical properties.