Low-cost laser sniffs out bombs

The physicists, from the University of St Andrews, have made a laser that can trace vapours emitted from explosives such as TNT.

Once developed, the scientists say the device will work like ‘an artificial nose for a robot dog’, sniffing out vapours at extremely low concentrations.

According to a statement, the technology could not only improve airport security, but could help to detect landmines and roadside bombs that emit dilute hidden clouds of vapour into the air.

The research, published this week in the journal Advanced Functional Materials, was carried out by Ying Yang, Graham Turnbull and Ifor Samuel.

Using a thin film of polyfluorene (essentially a light-emitting plastic) the group has created a laser that reacts with vapours from explosives. The laser light dims within seconds when the plastic comes into contact with even the tiniest emission of vapour.

The laser sensor can be reset by a blast of nitrogen gas.

‘Floating above a landmine in Iraq or Afghanistan, there’s a very weak, dilute cloud of vapours of explosive molecules that the bomb is made from,’ said Dr Turnbull. ‘We have shown that our lasers can rapidly sense these TNT-like molecules, frequently used in explosives, at extremely low concentrations.’

The team said that the laser could be built into a remotely controlled robotic device that could be despatched into a minefield to look for vapour clouds.

‘On a dusty road in Afghanistan there are relatively few things that might affect the laser output and it certainly could have potential in that area,’ said Dr Turnbull. ‘Essentially it’s making an artificial nose for a robot sniffer dog.’

One advantage over existing methods is that the new technology is relatively low cost since the plastic, polyfluorene, is widely used in plastic electronics.