Various institutes around the world have long touted the potential of breath testing as a form of early and non-invasive disease detection. Now a research team from Australia's University of Adelaide has developed a new kind of laser with the ability to detect low concentrations of gases, opening up even more possibilities for disease diagnosis and other applications such us measuring the concentration of particular greenhouse gases in the atmosphere.
The erbium-doped zirconium-fluoride-based glass fiber laser operates in the mid-infrared frequency range, which is the range where many hydrocarbon gases absorb light. The laser can produce 25 times as much light as lasers operating at a similar wavelength according to the researchers, paving the way for the detection of previously obscured, low concentrations of gases.
"This laser has significantly more power and is much more efficient than other lasers operating in this frequency range," says Ori Henderson-Sapir, PhD researcher and one of the study's authors. "Using a novel approach, we've been able to overcome the significant technical hurdles that have prevented fiber lasers from producing sufficient power in the mid-infrared."
The researchers report a light emission of 3.6 microns, what they say is the deepest mid-infrared emission from a fiber laser operating at room temperature.
"Probing this region of the electromagnetic spectrum, with the high power we've achieved, means we will be able to detect these gases with a high degree of sensitivity," says Project Leader Dr David Ottaway. "For instance, it should enable the possibility of analyzing trace gases in exhaled breath in the doctors' surgery."
Detecting certain particles and gases through breath-testing has proven valuable in the diagnosing of particular illnesses. In December 2013 a team of UK-based researchers began trialling a device designed to recognize certain chemicals in the breath of early lung cancer patients, while systems to detect asthma have been in use for some time.
As far as alternative potential applications for the laser go, the sky is the limit. The researchers cite the detection of the greenhouse gases methane and ethanol in the atmosphere as another use for their system due to its power, efficiency and ability to be easily transported.
"The main limitation to date with laser detection of these gases has been the lack of suitable light sources that can produce enough energy in this part of the spectrum," says Dr Ottaway. "The few available sources are generally expensive and bulky and, therefore, not suitable for widespread use."
The team's findings were recently published in the journal Optics Letters.
Source: University of Adelaide
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