Broad band terahertz time domain spectroscopy on polymers and organic electro-optic polymers.

摘要

Several polymers and two organic polymer composites were studied using terahertz time domain spectroscopy and analyzed using Duvillaret's method and a dynamic range analysis to determine their credible bandwidth. Terahertz time domain spectroscopy is a technique that allows us to determine the real index of refraction and the absorption of nonconductive materials in the terahertz band. These polymers are used as hosts to build organic composites for terahertz generation through optical rectification and detection via electro-optic (EO) sampling. Knowledge of their optical parameters is important when considering them as hosts for emitters and detectors. Also, the knowledge of these parameters over a wide bandwidth of is important in the determination of the degree of phase matching that these materials can have, for a given center wavelength of an optical pump pulse. Broad bandwidth and a clear spectrum were achieved with an air-plasma emitter and an EO polymer sensor. In this thesis a bandwidth that goes from 0.7 to 9 THz for the real index of refraction and the absorption coefficient for the majority of the polymers, is reported.