Multiwavelength fiber laser to ‘revolutionize’ gas detection

03 Oct 2017

Integrated mid-IR and supercontinuum sources will find applications in medicine, climate science and mining.

An international research group, led by scientists at Macquarie University, Sydney, Australia, has developed what it is calling a “world-first optical fiber technology” that can detect a wide range of gases with unprecedented sensitivity. The device has potential applications ranging from breath analysis to air-quality monitoring.

Details of the discovery, which has been published in Optica, include the development of an optical fiber device with an infrared laser coupled to an ultra-broadband supercontinuum generator. Researchers have never before managed to combine these two elements in a single optical system.

Gas detection

“The new supercontinuum technology that we’ve developed is capable of being used to detect an array of gases, including methane, carbon dioxide and nitrous oxide – gases that can be harmful to humans in high levels and have implications in climate change,” explained lead researcher Dr Darren Hudson from Macquarie University.

Over the past decade, researchers world-wide have worked to create high-brightness sources of infrared light. While this work has revolutionized the detection and measurement of a wide range of molecules, the currently available technology still typically requires large laser systems, optical lab conditions, and expert control. Macquarie’s new fiber optic-based system will make this technology much smaller and easier to use, commented Dr Hudson.

“While previous research has led to ultra-broadband supercontinuum sources, we have managed to squeeze this technology into a system that can be completely fiber integrated – known as an ‘all fiber’ system – protecting it from outside influences and making it much easier to use in an array of scientific and medical situations, including operating in harsh environments,” he added.

Key design elements of the new infrared-supercontinuum detector.

Key design elements of the new infrared-supercontinuum detector.

New fiber laser

To achieve the first all-fiber system, researchers first developed a new kind of fiber laser that emits infrared light in extremely short bursts (180 fs). They then fired these laser pulses into a special type of microwire fiber, developed by collaborators at McGill University and Laval University, both in Canada.

“The resulting supercontinuum performance of the new fiber optic technology matches the best performance from large laser systems, but in a package that could one day fit in the palm of your hand,” said Associate Professor Alex Fuerbach, co-leader of the research group that produced the study, from Macquarie.

The researchers are now looking to work with collaborators to test different ways the technology can be used. “As the new system could be capable of detecting trace gases in various environments, we are hoping to work with other groups to test its use in these applications, which could include breath analysis for early disease detection, environmental monitoring for emissions, climate change monitoring and in industrial settings where fracking and mining are taking place,” concluded Prof. Fuerbach.