Design and characterization of metamaterial building blocks using electric current multipoles

In contrast to ordinary materials, optical metamaterials can interact with light in unprecedented ways, enabling novel applications in, e.g., subwavelength imaging and optical cloaking. These extraordinary properties all originate from the excitation of higher-order multipoles in the building blocks constituting the metamaterial. Unfortunately, the knowledge of how to extract the contribution of higher-order multipoles is not well established. In fact, several studies on metamaterials rely upon erroneous quasistatic descriptions that fail to provide accurate results for realistic metamaterial building blocks.