Laser-based bomb-detector

Light could provide a simple yet effective way to detect hidden bombs, according to a patent from researchers from the Massachusetts Institute of Technology.Nitrotoluene vapours released by TNT and DNT explosives dramatically reduce an organic semiconducting polymer's ability to produce laser light, the patent says.So the researchers propose detecting these vapours using a thin layer of the polymer deposited onto a sheet of glass. The polymer would be excited with short light pulses so that it produces laser light. One end of the polymer is sealed so that the laser beam is produced from the other end, in a direction parallel to the glass.If the polymer film is exposed to TNT or DNT vapour the intensity of the laser should instantly drop by a factor of about a hundred. This change would then be very easy for an optical detector to sense, providing a quick alarm.This system could be incorporated into a handheld device to sniff out bombs hidden in suspect packages. But the device could even be sensitive enough to detect explosive buried underground, the patent claims.