THz Applications - Nonlinear Spectroscopy: SEED
The third & final application is SEED...Stimulated Emission Enhanced Detection - a non-passive, interrogative 'nonlinear spectroscopy' application where a known resonating THz frequency of the material in question is applied. If that material, an explosive in this case, is located within the frequency's sweep, the material will absorb some of the applied resonating frequency's energy.
This phenomenon is called 'excitation'...where the addition of a discrete amount of energy called excitation energy to a molecule results in a molecular alteration from its condition of lowest energy...or ground state...to one of higher energy...an excited state.
More: The SEED Project