Fe-Doped Polycrystalline CeO₂ as Terahertz Optical Material

Fe-doped CeO₂ is synthesized by ceramic method and the effects of Fe doping on the structure and properties are characterized by ordinary methods and terahertz-time domain spectrometer (THz-TDS) technique. Our results show that pure CeO₂ only has a small dielectric constant ε of 4, while a small amount of Fe (0.9at.%) doping into CeO₂ promotes densification and induces a large ε of 23. From the THz spectroscopy, it is found that for undoped CeO₂ both the power absorption and the index of refraction increase with frequency, while for Fe-doped CeO₂ we measure a remarkable transparency together with a flat index curve. The absorption coefficient of Fe-doped CeO₂ at frequency ranging from 0.2 to 1.8THz is less than 0.35cm^-1, implying that Fe-doped CeO₂ is a potential THz optical material.