Optical materials for the thz range

The properties of optical materials usable in the terahertz (THz) spectral range, which is the boundary between the optical and radio ranges, are examined. The relevance of the research field associated with the optics of THz devices is largely governed by intensified activity on creating lasers operating in the THz range and the discovery of substantial problems in the use of optical materials for these applications in general. The present study is devoted to analyzing the properties–especially optical properties–of the THz materials used. The characteristics are given, and the physical, chemical, and optical properties of conventional and new materials, including crystalline (silicon, sapphire, quartz, diamond, germanium, and silicon carbide), as well as a number of polymers (polymethylpentene, polyethylene, and polytetrafluoroethylene), are discussed and compared.