|Researchers at the Michingan State University, USA, announced on September 18, 2011 that they had developed a new laser which can accurately detect roadside bombs and help identify improvised explosive devices (IEDs), often used by terrorists. The device has the sensitivity and selectivity to scan large areas and detect IEDs that account for around 60 percent of military deaths in troubled coutries such as Afhanistan and Iraq.
Detection of explosive substances such as IEDs is extremely challenging because the environment injects a large number of chemical compounds which mask the select few molecules that one is trying to detect. But the new laser can make these distinctions even for quantities as small as a fraction of a villionth of gram.
According to the reasearchers, the laser combines short pulses that cause molecules in the explosives to vibrate, as well as long pulses that are used to 'listen' to and identify the differnet vibrations It is worth mentioning here that every kind of molecule has different vibrational frequencies that uniquely identify the substance, much like a fingerprint.
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