PS-THz imaging: Analysis of orientation and birefringence

An advanced THz imaging setup in reflection geometry is used to determine the optical axis and birefringence within an injection molded part made of a glass fiber reinforced polymer. By using a polarization sensitive detection method and a quasi-circularly polarized THz pulse the orientation of the fibers and the birefringence are determined in a single measurement without the need of rotating the polarization axis with respect to the sample or matching with a reference signal. We also propose an analytic algorithm to extract the optical parameters from the spectral components of the THz field.