Scientist develops bomb-detecting laser

A chemistry professor at Michigan State University developed a laser that can detect small traces of explosive chemicals on clothing and luggage, according to a recent article in Applied Physics Letters.

The development by Marcos Dantus, a professor and the founder of BioPhotonic Solutions, could allow for bomb-detection at security checkpoints. The laser could be used in a conveyer belt, similar to the way airports use X-ray scanners. The low-energy laser would be safe on luggage as well as passengers.

"Since this method uses a single beam and requires no bulky spectrometers, it is quite practical and could scan many people and their belongings quickly," Dantus said. "Not only does it detect the explosive material, but it also provides an image of the chemical's exact location, even if it's merely a minute trace on a zipper."

Dantus came up with the idea after a collaboration with Harvard University that developed a safe laser for cancer detection.

"While working on biomedical imaging, I began exploring additional applications," Dantus said. "We soon learned how effective it was for detecting traces of hazardous substances from distances up to 10 meters away."

The laser uses two pulses: one that resonates with certain chemical frequencies and one that emits a shadow pulse as a point of reference. The discrepancy between the two pulses shows the presence of explosive materials.

"The laser is not affected by the color or surface of clothes or luggage," Dantus said. "The resonant pulse and the shadow pulse are always in balance unless something is detected. Our method has Raman chemical specificity, excellent sensitivity and robust performance on virtually all surfaces."

Dantus said that with additional funding, a standalone prototype of the device could be developed in approximately one year.