Ytterbium thin disk laser paves the way for sensitive detection of air pollutants

Along with carbon dioxide, methane is the main cause of global warming. To accurately detect and monitor climate pollutants in the atmosphere, scientists at the Max Planck Institute for the Science of Light (MPL) have developed advanced laser technology.

A high-power ytterbium thin disk laser drives an optical parametric oscillator (OPO) to generate high-power, stable pulses in the shortwave infrared (SWIR) spectral range. This allows researchers to detect and analyze a variety of atmospheric compounds. This new method, which could play an important role in tracking greenhouse gas cycles and the effects of climate change, was recently published in the journal APL Photonics.

Short-lived pollutants play an important role in global warming. For example, methane is particularly relevant to the global greenhouse effect because its warming potential is 25 times higher than carbon dioxide. However, detection and monitoring of these contaminants is difficult for two reasons.

First, water vapor interferes with and overlaps the absorption spectra of many gases in the standard infrared range typically used for detection. Second, these pollutants are difficult to detect due to their volatile nature in the atmosphere. The new laser system delivers unprecedented detection sensitivity and accuracy by targeting the SWIR range where pollutants such as methane are strongly absorbed and water is minimally absorbed.

At the heart of this innovation is a ytterbium thin disk laser that generates high-power femtosecond pulses at megahertz repetition rates. This allows the system to excite OPOs and convert laser pulses into the SWIR range with incredible power and intensity.

The OPO operates at twice the repetition rate of the pump laser, providing stable and tunable SWIR pulses optimized for high-sensitivity spectroscopy applications. The team’s pioneering approach also integrates wideband high-frequency modulation of the OPO output, which improves the signal-to-noise ratio and further improves detection accuracy.

“The power scalability of ytterbium thin disk lasers allows the output of our laser systems to be scaled up to higher average and peak powers. By employing a system that accurately detects contaminants in real time, we This could help address some of the challenges we face in understanding climate change,” said Dr. Anni Li. . MPL student.

The ability of lasers to generate stable pulses at high power in the SWIR range is a game-changer for field-resolved spectroscopy and femtosecond field observations, a method that allows researchers to detect and analyze a wide range of atmospheric compounds with minimal interference. .

“This new technology has potential applications not only in atmospheric monitoring and gas sensing, but also in other scientific fields such as Earth-orbit communications, where high-bandwidth modulated lasers are required.” said Dr. Haniyeh Fatahi, the study’s principal investigator. project.

The researchers plan to further develop the system with the goal of creating a versatile platform for real-time contaminant monitoring and Earth-space optical communications.