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T-rays are based on the terahertz (THz) region of
the electromagnetic spectrum that is between infrared light and
microwave radiation. Until recently, researchers have had great
difficulty harnessing the potential of the THz region for lack of
suitable radiation sources. Advanced materials research has provided
new and higher power sources, and interest in THz sensing and imaging
has exploded as a result.
Objects at room temperature emit thermal energy in
the THz range that can be used to sense and image objects. A
particular advantage of T-ray systems is that they can also give
spectroscopic information about the composition of chemical and
biological material, and are safer for biological applications than
X-ray photons, that emit a million times more energy.
Advances presented allow sensing of extremely small
objects on the nanometer scale, as well as at large distances of more
than 100 meters - an essential improvement for national security
applications such as remote sensing of explosives. In conjunction with
NASA, THz imaging has also successfully detected defects in space
shuttle foam. Other T-ray applications could enable the label-free
characterization of genetic material, detect a C-4 explosive hidden in
the mail, and help researchers understand the complex dynamics
involved in protein folding.
Schmuttenmaer's research uses THz technology to
determine characteristics of photo-excited reactions, information that
cannot be acquired with any other technique. "We have also devised a
system that captures the THz pulse emitted during rapid intramolecular
charge transfer using two different dye molecules," he said. "In the
future we will use this method to probe photosynthetic and bacterial
reaction centers, and perhaps DNA." |
