Terahertz spectral signature of DNA macromolecules

In this paper, the transmission spectral characteristics of Bx-DNA, Bm-DNA, herring-DNA, salmon-DNA and aspen-DNA have been studied by terahertz-time domain spectroscopy (THz-TDS) in the frequency range of 0.5-2.5THz. The absorption peaks have the phenomenon of merger when the thickness of the samples decrease, and the refractive index increase as the thickness of the samples increasing. By compared with the absorption coefficient of different kinds of DNA molecules, we have found that the homologous species have more same absorption peaks than different species. We also have picked up five different DNA samples which absorption peaks are in the frequency range of 0.5-2.5 THz in the experiments and we want to establish the database of DNA terahertz spectroscopy and identify the DNA macromolecules.