Plasmon detector finds minute traces of chemical explosives

A team of researchers led by Xiang Zhang, UC Berkeley professor of mechanical engineering, has found a way to increase the sensitivity of a light-based plasmon sensor to detect minute concentrations of explosives.

Their findings were published yesterday, July 20 in Nature Nanotechnology.

They put the sensor to the test with various explosives – 2,4-dinitrotoluene (DNT), ammonium nitrate and nitrobenzene – and found that the device detected the airborne chemicals at concentrations of 0.67 parts per billion, 0.4 parts per billion and 7.2 parts per million, respectively.

The researchers noted that this is much more sensitive than the published results to date for other optical sensors.

‘Optical explosive sensors are very sensitive and compact,’ said Zhang, who is also director of the Materials Science Division at the Lawrence Berkeley National Laboratory and director of the National Science Foundation Nanoscale Science and Engineering Center at UC Berkeley. ‘The ability to magnify such a small trace of an explosive to create a detectable signal is a major development in plasmon sensor technology, which is one of the most powerful tools we have today.’