Datum der Disputation: 16.04.2002

The work presents the creation of a time-domain THz instrumentation that enables broadband measurements of complex material functions of both bulk samples and thin films in the frequency range from 100 GHz to 2.5 THz at temperatures 20-300 K. Among other original solutions, a novel convertible scheme has been realized. It allows experiments in classical transmission configuration, as well as THz reflection measurements with quick and easy change of incidence angle of THz radiation from 25 to 80 degrees. Various ways to overcome the problem of phase uncertainty are also proposed and tested. The convertible scheme can serve as a basis for new THz arrangements, e.g., for a time-domain THz ellipsometer. The setup has been applied to the study of complex THz transmittance of high-Tc superconductor thin films. The measured data on YBa2Cu3O6.95 films were analyzed in the framework of the two-fluid Drude-London model. The results on Tl2Ba2CaCu2O8, however, were impossible to fit with classical Drude expressions with one frequency-independent scattering rate. The material also exhibited unexpectedly high surface resistance at the frequencies around 1 THz and higher