New Laser Detects Low Gas Concentrations

A new type of laser can produce 25 times more light emission than other such devices that operate on a similar wavelength, allowing for detection of very low concentrations of gases.

The laser, developed at the University of Adelaide’s Institute for Photonics and Advanced Sensing and the School of Chemistry and Physics, will lead to breakthroughs such as disease diagnosis using breath analysis and remote sensing of critical greenhouse gases, researchers say. It shows “great promise as a very useful diagnostic and sensing tool,” said David Ottaway, project leader.

The laser uses an optical fiber and operates in the mid-IR frequency range, the same wavelength band where many important hydrocarbon gases absorb light. Research shows light emission at 3.6 µm, the deepest mid-IR emission from a fiber laser operating at room temperature. The laser also has the promise of efficient emission across a wavelength spectrum from 3.3 to 3.8 µm.

Researchers will now be able to detect such gases with a high degree of sensitivity, Ottaway said. Other potential applications include detection in the atmosphere of methane and ethane, which are important gases in global warming.

The laser should also enable things like analyzing trace gases in exhaled breath of patients during surgical procedures. With various diseases, small amounts of gases not normally exhaled can be detected in the breath, researchers say — for example, acetone can be detected in the breath of a person with diabetes.

The work is published in Optics Letters.

For more information, visit www.adelaide.edu.au.