Terahertz homodyne imaging for inspection of low absorbing objects

Terahertz (THz) imaging of low absorbing objects is evaluated both in direct and homodyne set-ups at 0.3 THz and 0.6 THz at room temperature. Dynamic range increase by more than two order of magnitude in homodyne detection scheme is shown. Phase shift in homodyne approach is realized with no moving optical elements by using paper sheets. It is shown that the homodyne detection scheme is a very promising for identification of objects exhibiting low absorption of THz radiation, for instance, paper tissue, nitrile and low-density polyethylene concealed in textile.