  Contrary to what might be expected, when an organic dye is sputtered onto an
opaque holey metal film, transmission bands can be observed at the absorption
energies of the molecules. This phenomenon, known as absorption-induced
transparency, is aided by a strong modification of the propagation properties
of light inside the holes when filled by the molecules. Despite having been
initially observed in metallic structures in the optical regime, new routes for
investigation and applications at different spectral regimes can be devised.
Here, in order to illustrate the potential use of absorption induced
transparency at terahertz, a method for molecular detection is presented,
supported by a theoretical analysis.
