还原论视角下的时变超构材料构建与等效媒质理论研究

Construction of Time-Varying Metamaterials and Temporal Effective Medium Theory from the Perspective of Reductionism

等效媒质理论是从微观角度出发,根据复合材料的结构特点,研究其宏观意义上材料参数的方法。将空间等效媒质理论推广到时间等效媒质理论,以时变声学超构材料为例,从理论上推导超构材料的材料参数在时间上以高频率调制时,其等效参数形式。基于还原论思想,在COMSOL Multiphysics数值仿真软件中设计时变人工原子进而构建时变超构材料,从数值上验证时间等效媒介公式的正确性,进而扩展等效媒质理论体系。

In the teaching of physics graduate students,a kind of macroscopic material is usually reduced to the basic material unit based on reductionist thinking,and to search for the interaction between the units,then the macroscopic material will be reconstructed from the bottom up and the properties are described by macroscopic physical quantities.Effective medium theory is a method to study the macroscopic parameters of materials from the microscopic point of view and according to the structural characteristics of composite materials.This paper mainly extends the spatial effective medium theory to the temporal effective medium theory.Taking a time-varying acoustic metamaterial as an example,the effective parameter form is deduced theoretically when the material parameters of the metamaterial are modulated at a high frequency in time.Based on the reductionist theory,artificial time-varying atoms were designed in COMSOL Multiphysics numerical simulation software to construct time-varying metamaterials,and the correctness of the formula of effective temporal media was numerically verified,for expanding the effective medium theory system in existing textbooks.