Spectroscopic Study of Containers and Their Content Using a High-Resolution THz System

High-resolution measurements of spectral absorbance in the THz domain were performed to assess the detection feasibility of concealed materials. Spectral data of common materials used to form containers and some biological materials (DNA, tryptophan) are presented. We study the spectral range of 100-600 GHz, where atmospheric transmission allows remote sensing to reasonable ranges. Special care was taken to avoid the appearance of periodical spectral artifacts caused by the interference of multiple reflections from sample surfaces. They were removed either by algebraic postprocessing or by system adjustment to the Brewster angle that eliminates surface interface reflections of the
p
-polarization. These spectral measurements form a basis for a spectral library upon which detection and discrimination algorithms can be developed.