Current technology is too cumbersome for this kind of rapid detection and response. But new advances in liquid and gas phase chemical sensing being made at the Georgia Institute of Technology may lead to the development of palm-sized sensing tools that can provide the instant detection needed to stop such an attack.
Using small quantum cascade lasers, researchers at Tech, along with colleagues from Tel-Aviv University and OmniGuide Communications, have built and demonstrated a prototype handheld gas phase chemical sensing device and a liquid phase sensing device. The details appear in the July 15, 2005 issue of Analytical Chemistry and the May 9, 2005 issue of Applied Physics Letters.
The quantum cascade laser is the key to scaling down midinfrared chemical sensing tools to fit in the palm of the hand, said Boris Mizaikoff, associate professor in the School of Chemistry and Biochemistry at Georgia Tech.
"This diode laser light source emits midinfrared frequencies, operates at room temperature and is small roughly the same size as the laser you use in a laser pointer or CD player," said Mizaikoff.
Almost every organic molecule has a very distinctive absorption pattern in the midinfrared range (roughly between three and 20 microns) Illuminating molecules with a laser tuned to its fingerprint frequency will cause the molecules to vibrate as they absorb radiation at that frequency.
Detecting a chemical is as simple as illuminating a small volume of gas or liquid with a laser. If the laser is tuned to a characteristic absorption frequency of benzene, for example, and ben
Contact: David Terraso
Georgia Institute of Technology