LAUSR

Abstract The design of novel epsilon-near-zero (ENZ) medium is always the one of focus in electromagnetic field. It is an important and universal method to realize ENZ material by multi-layered isotropic film structures based on the equivalent medium theory. However, the ENZ material designed based on this theory is anisotropic and e-near-zero is only along a specific direction, which greatly limits its application scope. Therefore, the realization of truly isotropic equivalent ENZ medium is significant for the development of novel optical devices. In this paper, we modify the equivalent medium theory, derive the equivalent parameters formula of multi-layered structure of anisotropic alternating films firstly, and a novel multi-layered Ag/SiC film structures is designed to realize an isotropic equivalent optical ENZ medium based on the above theory. This work perfects the equivalent medium theory system, provides theoretical guidance to improve the design and preparation of optical ENZ material in the future, and the film structure mentioned in this work has also significance for the realization of specific optical ENZ material.