Australian researchers have created a laser that can “smell” different gases.

Scientists from the University of Adelaide say the new device could be used for environmental monitoring, detecting industrial contamination, or even diagnosing disease by “smelling” the breath.

The laser can differentiate between different gas compounds in a sample like the sensitive nose of a bloodhound, but rather than smell, it uses patterns of light absorption to measure the composition of the sample.

Tests so far have seen the laser measure the amount of carbon dioxide in a gas sample in under one second, with high accuracy and precision.

It exploits a Nobel-prize winning technology, developed by US and German scientists, called an ‘optical frequency comb’. This ‘laser comb’ generates millions of different light frequencies or colours at once.

The researchers pass this special light through a sample of gas where each gas molecule absorbs a distinctive set of colours. The pattern of light absorption is a unique fingerprint of the gas composition of the sample.

While it is designed largely for atmospheric modelling, the team also aims to use the laser comb to unravel the chemical composition of the exhaled breath – in this much more complex situation they hope to find tell-tale chemical signs that point to underlying disease.

The ultimate goal is to use the laser as a screening tool – to discover a serious illness even before the patient is aware of the condition.