テラヘルツ時間領域分光法による薄膜・表面の物性評価

抄録

Basic concept of recently-developed terahertz time-domain spectroscopy and linear and nonlinear terahertz responses of thin solid films have been reviewed. The ferroelectric soft mode driven to the anharmonic region was observed in SrTiO₃ thin films using a few-cycle intense terahertz pulses. The metallic surface states of Bi ultrathin films were detected in terahertz transmittance measurements. The superconducting gaps in MgB₂ and YBCO films were observed using broadband terahertz time-domain spectrometer. These results demonstrate the promising capability of terahertz time-domain spectroscopy for characterization of physical properties of thin films and the surface states.