Making light work of pollutant detection

17 Jun 2002

Detecting pollutants in the atmosphere could be made much easier, following a British development. Physicists at the Defence Evaluation and Research Agency (DERA) at Portsdown West in the UK have designed a system that sends a single laser beam containing many wavelengths at one go. Normally, to detect a mixture of pollutants, many different laser beams of the appropriate wavelength have to be shone into the atmosphere in turn - a slow and cumbersome process.

DERA announced the development at the Institute of Physics Applied Optics and Optoelectronics Conference in Loughborough, UK, on 18 September. The system uses a crystal in an optical parametric oscillator (OPO). By setting the input laser beam, crystal and OPO cavity at particular angles, a continuous range of wavelengths can be produced.

Although the original system was developed by DERA, one of the first applications was for the US Army to enable the fast detection of airborne aerosols. However, DERA says that it is equally suited to the roadside monitoring of particles from car exhausts. It could also, says DERA, be used to produce different colours in laser shows instead of the ubiquitous green, and the device could form the basis of new types of colour projection systems.