Effective material parameter retrieval for terahertz metamaterials

Metamaterials, which are generally composed of subwavelength scale metallic structures, have been the subject of intensive research in recent years. Because their effective electromagnetic properties can be engineered by designing subwavelength scale metallic structures, called meta-atoms, these artificially constructed materials are expected to lead to many new developments in the field of photonics. Furthermore, the terahertz (THz) frequency range has many important applications such as security detection, sensing, and biomedical imaging. Because many natural materials are inherently unresponsive to THz radiation, the natural materials that can be applied in devices in order to manipulate THz waves are very limited. Accordingly, the development of metamaterials with unusual optical properties in the THz frequency range has generated intense interest among researchers. In this part, design methods for metamaterials in the terahertz frequencies are introduced. This method is based on the unit cell design and S-parameter retrieval technique. Following a brief introduction to the method, some examples of terahertz metamaterial design will be presented in the last section.