Reviewed by Lexie CornerNov 18 2024
According to a study published in APL Photonics, scientists at the Max Planck Institute for the Science of Light (MPL) have developed an enhanced laser technology designed to accurately detect and monitor climate pollutants in the atmosphere.
The optical parametric oscillator pump by ytterbium thin disk laser. Image Credit: Axel Griesch
Methane, like carbon dioxide, is a significant contributor to global warming.
A high-power ytterbium thin-disk laser powers an optical parametric oscillator (OPO), which generates steady, high-power pulses in the short-wave infrared (SWIR) spectral band. This enables researchers to detect and analyze a wide range of atmospheric compounds. This innovative technology plays a crucial role in tracking greenhouse gas cycles and understanding the impacts of climate change.
Short-lived pollutants have a notable impact on global warming. Methane, for instance, is especially relevant to the greenhouse effect, as its warming potential is 25 times greater than that of carbon dioxide. However, detecting and monitoring these pollutants is challenging for two main reasons.
Firstly, the absorption spectra of many gases in the conventional infrared wavelengths often used for detection overlap and are interfered with by water vapor. Secondly, because these pollutants are volatile in the atmosphere, they are difficult to trace. The new laser technology overcomes these challenges by focusing on the SWIR band, where pollutants like methane absorb strongly, but water vapor has minimal absorption.
The ytterbium thin-disk laser, which generates high-power, femtosecond pulses at megahertz repetition rates, is central to this breakthrough. This enables the laser to pump an OPO, which transforms pulses into the SWIR region with exceptional intensity and power.
The OPO produces steady, adjustable SWIR pulses that are ideal for high-sensitivity spectroscopic applications while operating at twice the repetition rate of the pump laser. Furthermore, the team’s innovative approach incorporates broadband, high-frequency modulation of the OPO output, enhancing the signal-to-noise ratio and enabling even more precise detection.
The output of our laser system can be scaled to higher average and peak power, due to the power scalability of ytterbium thin-disk lasers. Employing the system for the accurate detection of pollutants in real time allows deeper insights into greenhouse gas dynamics. This could help address some of the challenges we face in understanding climate change.
Anni Li, Ph.D. Student, Max Planck Institute for the Science of Light
Field-resolved spectroscopy and femtosecond fieldoscopy, techniques that enable researchers to detect and study a wide range of atmospheric compounds with minimal interference, are enhanced by the laser's ability to produce high-power, steady pulses in the SWIR band.
This new technology is not only applicable to atmospheric monitoring and gas sensing, but also holds potential for other scientific fields such as earth-orbit communication, where high bandwidth modulated lasers are required.
Dr. Hanieh Fattahi, Study Lead Researcher and Research Group Leader, Max Planck Institute for the Science of Light
The researchers plan to develop the system further to create a flexible platform for Earth-to-space optical communications and real-time pollutant monitoring.
Journal Reference:
Li, A. et. al. (2024) 0.7 MW Yb:YAG pumped degenerate optical parametric oscillator at 2.06 μm. APL Photonics. doi.org/10.1063/5.0230388