After laying over the ground for about 30 minutes,the chemical sensing system is activated by an ultra-violet light to detect the organic compounds that explosives like TNT emit. The system can even sense plastic explosives like HMX, a compound used in explosives during World War II. When emissions are sensed, the fluorescent color darkens and a circle appears, identifying where the vapors are coming from.
"A UV light may be applied as a searchlight and coupled with a digital camera, so the results could be transmitted back to the control center," said Ying Wang, a scientist on the project.
If no threat is found, the film maintains its fluorescence and doesn't get darker. The process takes minutes and is relatively cheap thanks to the thin and lightweight material than can span a large area. Engineers from UConn point out the sensor could even be incorporated into a small paper test strip for a low-cost method of detection. Further testing will be under way soon. Dr. Wang told Discovery News that a large-scale field test in Sweden is in the process.