7 GHz resolution waveguide THz spectroscopy of explosives related solids showing new features

The vibrational modes of the explosive related solids 2,4- and 2,6-DNT have been measured with waveguide THz time-domain spectroscopy (THz-TDS) to unprecedented precision. Dramatic sharpening of spectral features upon cooling beyond 80 K to 12 K is observed, illustrating the high quality and alignment of the polycrystalline thin films. Many of the observed features have linewidths below 15 GHz. These linewidths are approximately 8 times narrower than for the corresponding measurements via conventional THz-TDS with cooled pellets. For the 2,4-DNT, the line narrowing resolved 19 absorption features compared to only 7 features with the corresponding pellet measurement. (C) 2008 Optical Society of America.