It is known that the particle chain can be served as a waveguide to guide the electromagnetic wave in the subwavelength scale and the metallic particle chain can only support the transverse electric (TE) mode (the magnetic field is perpendicular to the propagation direction). In this work, the composite metal-dielectric chains are constructed as the rod arrays in form of a straight line, a zigzag edge, or a combined double chains, in which both the TE mode and the transverse magnetic (TM) mode (the electric field is perpendicular to the propagation direction) can be supported. Based on the Mie theory and multiple scattering theory, the dispersion curves for different chains can obtained rigorously so that the dependence of the edge states on the structure parameters and symmetry of the chains can be examined. As a result, the loss can be reduced and the frequency of the surface plasmon polariton can be adjusted. In addition, the idea can be further extended to composite chains composed of the dielectric and magnetic particles so that the nonreciprocal features can be modulated.
Based on the Mie theory and the multiple scattering theory, we have performed a comparative study on the beam steering by two kinds of systems which are composed of either a single layer of dielectric rods or a single layer of ferrite rods. It is shown that for both systems the incident Gaussian beam can be negatively refracted and with appropriate adjusting the related parameters the total reflection can be implemented as well. However, the essences to realize the phenomena are different with the former system keeping the reciprocal property and the latter one exhibiting nonreciprocal property. For the dielectric system, to switch the functionality the resonance is tuned by the size of the dielectric rod, while for the magnetic system it is realized by simply reversing the bias magnetic field due to the nonreciprocity of the ferrite materials under the bias magnetic field (BMF). By examining the field profiles we can find more details, where the dielectric system is operable for the transverse electric (TE) mode and the magnetic system is effective for the transverse magnetic (TM) mode. The electromagnetic field patterns associated with the single dielectric rod and ferrite rod exhibit different forward and backward scattering features in case of negative refraction and total reflection, which is further enhanced by the constructive and destructive interference of scattering fields from the all the rods in the particle array. The results are significant for the understanding of resonance in reciprocal and nonreciprocal systems and also inspiring for the flexible beam steering.