Laser Method Promising For Detecting Trace Chemicals In Air

Researchers have developed a new laser-based method that can detect electric charges and chemicals of interest with unprecedented sensitivity. The new approach could one day offer a way to scan large areas for radioactive material or hazardous chemicals for safety and security applications.

The new technique, called mid-infrared picosecond laser-driven electron avalanche, detects extremely low charge densities — the number of electric charges in a certain volume — in air or other gases. The researchers were able to measure electron densities in air produced by a radioactive source at levels below one part per quadrillion, equivalent to picking out one free electron from a million billion normal air molecules.

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