Rhodes scientists turn off the green light

Scientists at Rhodes University in Grahamstown have developed a simple dye that may hold the solution to pranksters who flash green lasers at aircraft, temporarily blinding the pilot and putting lives at risk.

Their product has potential for military and civilian aircraft. While there are goggles on the market that block green laser light, they are not ideal because they also block harmless green light from all other sources — including aircraft instruments.

There has been a steep rise in reports to the Civil Aviation Authority of pilots being "lasered" while landing aircraft, with more than 200 such incidents noted in the past year, according to the Council for Scientific and Industrial Research’s National Laser Centre principal Aletta Karsten.

Most of the laser attacks are carried out with small powerful lasers bought at hobby shops or over the internet, which are intended for stargazers to point out stellar constellations.

"They shine the laser at the aircraft when it comes in for landing. The chance of hitting a pilot in the eye is small, but scratches on the aircraft canopy scatter the light and it causes a big green flash that can blind the pilot for tens of seconds. I have heard of pilots still struggling to see after they land," said Dr Karsten.

Rhodes chemists are developing thin polymer films embedded with pthalocyanine dyes that block green laser light but allow other wavelengths to pass through, said holder of the medicinal chemistry and nanotechnology research chair Tebello Nyokong.

Phthalocyanine is an intensely blue-green-coloured aromatic compound widely used in dyeing.

A key characteristic of the Rhodes chemists’ film is that its green light-blocking properties are only activated when green laser light strikes the pthalocyanines, which means that most of the time it allows a pilot to see ordinary green light from instruments or signs on a runway. The idea is to apply the film to glasses or an aircraft’s cockpit canopy.

"We are chemists, so our job is nearly done. We have shown we can make thin films that protect pilots. Someone else needs to determine if it is (commercially) worthwhile," said Prof Nyokong.

Written by:  Tamar Kahn

Picture credit:  Thinkstock

  • This article was published on Business Day.