Advanced laser technology detects atmospheric pollutants

A high-power ytterbium thin-disk laser drives an optical parametric oscillator (OPO) to generate high-power, stable pulses in the short-wave infrared (SWIR) spectral range. This allows researchers to detect and analyse a variety of atmospheric compounds.

The technology, which could help track greenhouse gas cycles, is detailed in APL Photonics.

Detecting and monitoring the pollutants such as methane is challenging as water vapour interferes and overlaps with the absorption spectra of many gases in the standard infrared ranges normally used for detection. Also, pollutants are difficult to detect due to their volatile presence in the atmosphere.

By targeting the SWIR range, where pollutants such as methane absorb strongly while water absorption remains minimal, the new laser system is claimed to offer unprecedented detection sensitivity and accuracy.

Key to this advance is the ytterbium thin-disk laser, which produces high-power, femtosecond pulses at megahertz repetition rates. This allows the system to pump an OPO, converting laser pulses to the SWIR range. Operating at twice the repetition rate of the pump laser, the OPO is said to deliver stable, tuneable SWIR pulses optimised for high-sensitivity spectroscopic applications.