An illuminating tool

Using small quantum cascade lasers, researchers at the Georgia Institute of Technology, 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 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.