Current sensor aids TAG analysis

1 min read

A low-noise current controller developed at Pacific Northwest National Laboratory could aid precise analysis of trace atmospheric gases (TAGs) by delivering stable power to lasers in gas sensors.

The low-noise current controller was developed at the US Department of Energy’s Pacific Northwest National Laboratory. The technology was recently licensed to Bozeman, Montana-based Wavelength Electronics by Battelle, which operates PNNL for the UD Department of Energy (DOE).

Scientists often analyse atmospheric gas concentrations with laser-based sensors. Researchers sample air at sites of interest, such as on the ground near power plants or at high altitudes from aircraft. The sensor instrument then directs a laser through the sample. Based on how much laser light is absorbed by the sample, scientists can determine the specific gases present and their concentrations.

But smaller concentrations of certain gases can be challenging to analyse. One particular problem occurs when ’noises’, or random fluctuations, exist in a laser’s wavelength and line width. Such noise prevents researchers from making precise readings.

PNNL scientists reduced this problem by developing a low-noise current controller. The device reduces the noise on the laser’s power source, allowing scientists to detect smaller levels of trace gases. The controller is claimed to be the lowest noise controller on the market specifically for extra-sensitive sensors that use quantum-cascade lasers, also called QCLs.

Sensors made with QCLs emit light in a wavelength region that many trace gases strongly absorb. QCL-based sensors become even more sensitive when they are powered with low-noise current controllers such as PNNL’s.

Wavelength Electronics is looking to launch products that incorporate PNNL’s low-noise current-controller technology by the end of this year that will specifically target the QCL market. Other models will be available to work with laser diodes that could be used in microbial detection, skin-cancer scanning, DNA sequencing, remote measurements and testing with VCSELs, or vertical-cavity surface-emitting lasers, a kind of laser diode.