Study On Topological Properties In Metal Nanoparticle Arrays

In this paper,we theoretically study the topological optical properties in one-dimensional zigzag chains composed of metal nanoparticles.The topological phase transition in the system is realized by controlling the polarization of the external optical field,which is feasible in experiments in contrast with changing the structural parameters.The dipole responses of the system with different bond angles to the external field of arbitrary linear polarization are calculated.It is found that a wide domain of polarization angles are available for a given zigzag chain to observe the polarization-induced topological transition.We verify the accuracy of nearest-neighboring approximation,and give a detailed derivation process for implementing the SSH model using metal nanoparticle arrays.In addition,we have also calculated the field intensity distribution of the system,and we can see that edge states appear when the system is topologically nontrivial,which further proves the effectiveness of modulation by polarization.The system,an easily-implemented platform to study physical phenomena in topological photonics,might has novel applications in nano-scale optical device manufacturing.The article also explores the topological characteristics of linear arrays of metal nanoparticles.Under the action of the external field,edge states are generated in the model of the specific structure.We deduce the interaction of adjacent spheres,and obtain the dipole moment of each metal sphere in the system.We also calculate the dipole moment of each particle in a precise way,and the results of the two methods are compared.Finally,the robustness of the edge states is verified by randomly changing the position distribution of metal nanoparticles.