A tiny laser sensor can detect explosives

A team of engineers from UC Berkeley in the U.S has developed a new technology that can detect explosives in smaller amounts than ever before.

They used a tiny nanoscale plasmon sensor, which consists of a layer of cadmium sulfide on top of a sheet of silver, with a layer of magnesium fluoride in the middle. (But you probably already knew that.) It’s smaller than any other bomb-detection device on the market, and appears to be much more sensitive.

The researchers tested it with different explosives, including DNT, ammonium nitrate and nitrobenzene, and it successful detected the airborne chemicals of each at concentrations of 0.67 parts per billion, 0.4 parts per billion and 7.2 parts per million, respectively. This is a much better result than for any existing sensors.

The tiny device was especially effective when it came to detecting explosives that are more electron deficient, which should be good news for finding pentaerythritol tetranitrate (PETN) in future. PETN is popular among terrorists because a little goes a long way, and being a type of plastic, it can’t be spotted by x-ray scanners. It can even be hidden in mobiles and other gadgets. But the team says that their sensor technology could lead to the creation of a bomb-detecting chip that detects trace amounts of vapour from the explosive’s small molecules.

It also has the potential to be incorporated into landmine-detecting devices, as existing products are not designed to find plastic components. Zhang said, ‘The ability to magnify such a small trace of an explosive to create a detectable signal is a major development in plasmonsensor technology, which is one of the most powerful tools we have today.’

The downside is that, as little as this new sensor is, it’s far less cute than a bomb-sniffing dog. But if it offers us even less chance of dying in a horrific explosion, the trade-off is probably worth it.

Image via Zach Dischner’s Flickr.

Diane Shipley