Swedish researchers have developed a groundbreaking laser method that can rapidly identify chemical weapons and dangerous bacteria directly in the field – without needing to send samples to a laboratory. The technology is based on the principle that chemicals emit unique light signals when struck by laser.

Hazardous chemicals can be found everywhere – as pollutants in waterways, pesticides in food, or in the form of synthetic substances created to cause harm, such as narcotics and chemical warfare agents. Protecting people from these substances requires fast and reliable detection methods.

A new dissertation from Umeå University in northern Sweden demonstrates how laser technology can solve this problem.

Rasmus Öberg, doctoral student at the Department of Physics and the Industrial Doctoral School at Umeå University, has developed methods in collaboration with the Swedish Defence Research Agency (FOI) that can identify extremely small quantities of hazardous chemicals.

Unique "fingerprint" from each chemical

The principle is based on different molecules reacting differently when exposed to laser light.

— All hazardous chemicals consist of molecules with specific appearances and properties that make them dangerous. When these chemicals interact with light, for example from a laser, they emit a 'fingerprint' – a light signal that is unique to that particular chemical, says Öberg.

The methods can be used in conflict zones or for environmental monitoring to provide a rapid initial assessment of potential hazards. The results can then be followed up with more thorough laboratory analyses if needed.

— Traditional methods for detecting hazardous chemicals are often quite cumbersome and difficult to use outside the lab. With portable instruments and surfaces that amplify the light signals from the chemicals, we can take these methods into the real world. The collaboration with FOI, which has extensive experience working with hazardous substances, has been invaluable in this work, he continues.

Also works against bacteria

The dissertation also shows that similar laser technology can be used to trace dangerous bacteria and bacterial spores. This has great significance for the food industry and healthcare, where antibiotic-resistant bacteria pose a growing threat.

— Biological substances are often more complicated to detect, but by isolating characteristic chemicals from these bacteria and bacterial spores, we can detect even them in relatively small quantities. This is an exciting complement to established biological detection methods such as bacterial culture and PCR, notes the doctoral student.

The researchers now hope for continued development of the technology for use in more contexts where rapid and reliable analysis is crucial. In the long term, the methods could strengthen preparedness and security in areas such as environment, defense, and health.