Nonreciprocal Transmission Of Electromagnetic Waves By Magneto-optical Mediums

With the development of information technology,Magneto-optical materials(MOMs)have attracted more and more attentions due to special electromagnetic characteristics and novel applications,such as electromagnetic wave control,information storage,super-resolution imaging,Cloaking,and isolators ets.In this paper,the electromagnetic wave propagation characteristics of the 1D and 2D multi-layer filled with the dispersion magneto-optical material have been investigated.The nonreciprocal transmission properties under the external magnetic field have been analyzed.The main research contents are as follows:(1)We have investigated nonreciprocal transmission properties of three-layers structure filled with magneto-optical medium and normal medium.Based on the transfer matrix method,the total transmission coefficient for one dimension structure with anisotropic mediums has been deduced.When two sides layers with magneto-optical medium loaded opposite external magnetic field,time-reversal symmetry of transmission properties have been broken.Numerical results show that the nonreciprocal transmission properties have been influenced by the external magnetic fields,incident angle and thickness of the normal medium layer.(2)A nonreciprocal transmission structure is designed using a one-dimension multi-layer medium,which consists of two asymmetric structure filled with the magneto-optical dispersive mediums.The total transmission coefficient have been deduced using the transfer matrix method.Numerical results further provided evidence for the occurrence of the nonreciprocal optical Tamm states(OTSs).These states are affected by layers thickness of layers,incident angles,and the externally applied magnetic fields.(3)A one-dimensional nonreciprocal structure comprising two asymmetric multilayers filled with magneto-optical dispersive media and a defect layer is designed.The nonreciprocal optical Tamm states(OTSs)are excited at the interface of the two asymmetric multilayer structure with an opposing external magnetic field.With the excitation of the nonreciprocal OTSs,the numerical results show that the waves can be transmitted and be reflected in one-way.These nonreciprocal properties are affected by the layers thickness of the defect layer,the angles of incidence,and the externally applied magnetic fields.(4)The propagation characteristics of the electromagnetic wave excited by TE mode are studied in the one-dimensional compound photonic crystals.Based on the transfer matrix method,the transmission and reflection coefficients of the electromagnetic wave of TE mode are obtained,and the transmission properties of the electromagnetic wave in the asymmetric one-dimensional photonic crystal of TE mode are simulated numerically.The results show that there are two nonreciprocal transmission peaks in the photonic band.With the increasing of incident angle,the nonreciprocal transmission peaks are blue shift,and the nonreciprocalproperties are enhance by the increasing of the space of nonreciprocal frequencies.In addition,the gyromagnetic permeability of the gyromagnetic medium is main factor to determine the nonreciprocity in the compound photonic crystals.With the reduction of gyromagnetic permeability,the nonreciprocal frequencies appears redshift,and nonreciprocal properties decrease by the decrease of the space of nonreciprocal frequencies.(5)A composite 2D photonic crystal structure with magneto-optical materials and ordinary media is constructed and its electromagnetic propagation characteristics are studied.The energy band structure of the super cell of composite structure is analyzed by the plane wave expansion method.It can be seen that there is a undirectional mode in the forbidden band region of the two composite structures,which is a boundary mode wave at the interface of the two composite photonic crystals,and different from the general propagation mode.This special boundary mode is affected by the external static magnetic field.Through air defect in a photonic crystal composed of ordinary medium,the propagation wave is obtained by a line source,and different directions of the propagation wave in the boundary mode are obtained through different directions of the external magnetic field.