CU Boulder SAURON sensor spots airborne chemical threats

11 Apr 2024

Laser frequency combs will allow platform to detect species of concern among multiple atmospheric signals.

Combing the scene: methane detection

A project group including the University of Colorado Boulder (CU Boulder), Caltech and the University of California Santa Barbara (UCSB) is developing a device for spotting possible chemical threats in the atmosphere.

Christened the Standoff Aerosol measUrement Remote Optical Network, or SAURON, the new platform is intended in particular to identify aerosols present in the air.

Several chemicals can pose hazards when present as atmospheric aerosols, including polycyclic aromatic hydrocarbons, ammonium nitrate, and the opioid drug fentanyl.

The SAURON project, funded by the US Intelligence Advanced Research Projects Activity (IARPA) and running until 2027, will employ laser frequency combs, in which laser output is divided into separate regularly spaced spectral lines. These sources are potentially versatile gas detection devices, capable of higher sensitivity than other spectroscopic analysis approaches.

Frequency combs have been a topic of research at CU Boulder for some time, including the university's joint work at the JILA research center operated with NIST. JILA has applied frequency combs to topics including the real-time diagnosis of disease via breath analysis, where frequency combs allow the necessary combination of broad spectral range and fine resolution.

During the Covid-19 pandemic, the same principle was expanded and combined with machine learning to detect SARS-CoV-2 infections, reflecting how "frequency comb technology has the potential to non-invasively diagnose more health conditions than other breath analysis techniques while also being faster and potentially more accurate," according to JILA.

Rapid warning of failures or leaks

CU Boulder has already applied frequency combs to the monitoring of atmospheric methane in the atmosphere, helping to study the molecule's role as a greenhouse gas. In January 2024 LongPath Technologies, a CU Boulder spin-out specializing in methane detection, received conditional approval for a $189 million loan guarantee from the US Department of Energy to accelerate the scale-up of its laser-based monitoring systems.

The team behind SAURON envisage a battery powered device portable enough to be moved to locations where aerosols have been released into the atmosphere, such as the sites of industrial accidents.

"The lasers will run off of batteries, so you can deploy them at an airport, on city blocks or in industrial sites where they use hazardous materials," said CU Boulder's Scott Diddams. "Right off the bat, people would know if there was a failure or a leak."

Making the device compact will involve the use of integrated photonics technology, bringing into the project research underway in the Quantum Engineering Initiative at CU Bulder. Recent breakthroughs at Nexus Photonics and hQphotonics, spin-outs from SAURON partners UCSB and Caltech respectively, will also play a part.

"SAURON is an example of researchers at CU Boulder taking advances in fundamental science and transforming them into tangible technologies that could one day safeguard people," commented project leader Greg Rieker of CU Boulder. "We’re taking technologies that have been developed for quantum science and are translating them for a wide range of applications."