T-ray spectroscopy of biomolecules

In the past few years it has been shown that the THz spectra of many polycrystalline biomolecules show very distinct, characteristic features. The fact that these specific signatures can be used to identify many samples such as pharmaceuticals, illicit drugs, and explosives through a wide range of common packaging materials has spurred an increased commercial interest in THz-TDS and imaging. However, most of these signatures that occur in the spectra of polycrystalline samples originate from phonon-like vibrations of the well-ordered intermolecular structure. The spectra of larger biomolecules, due to the lack of such a long-range order, quite often show only a broad, featureless absorption. Furthermore, the sample preparation becomes more and more important, as many of these sample are only available in very small quantities or in liquid solutions. These hurdles constrict many biomedical applications of THz spectroscopy. In this presentation, we will show, based on a wide range of examples, the potential that THz-TDS and imaging hold for biomedical applications and discuss possibilities for overcoming the hurdles that currently obstruct their application.