Abnormal dispersion of polymer films in the THz frequency region

Transmission and reflection measurements on various polymer films were performed in the THz frequency region, and the dielectric function was calculated by the Debye model to interpret the data. The ε0 and ε∞ obtained in our analysis show good agreement with the ε0 from the electric measurements in MHz–GHz frequency region, and the ε∞ calculated from the refractive index in the visible region. The abnormal dispersion was confirmed to appear in the THz frequency region, and the dispersion was not observed in non-polar polymers. This evidence shows the dispersion is due to the orientation polarization of polymers.