World’s smallest terahertz detector developed

Molecules could soon be ‘scanned’ in a fashion similar to imaging screenings at airports, thanks to a new detector developed by physicists.

The detector may have the ability to chemically identify single molecules using terahertz radiation — a range of light far below what the human eye can detect.

“Our invention allows lines to be ‘written and ‘erased’ much in the manner that an Etch A Sketch toy operates,” said study co-author Jeremy Levy from the University of Pittsburgh.

“The only difference is that the smallest feature is a trillion times smaller than the children’s toy, able to create conductive lines as narrow as two nanometers,” Levy said.

Terahertz radiation refers to a colour range far beyond what the human eye can see and is useful for identifying specific types of molecules.

This type of radiation is generated and detected with the help of an ultrafast laser, a strobe light that turns on and off in less than 30 femtoseconds (a unit of time equal to 10-15 of a second).

Terahertz imaging is commonly used in airport scanners, but has been hard to apply to individual molecules due to a lack of sources and detectors at those scales.

“We believe it would be possible to isolate and probe single nanostructures and even molecules — performing ’terahertz spectroscopy’ at the ultimate level of a single molecule,” said Levy.

“Such resolution will be unprecedented and could be useful for fundamental studies as well as more practical applications,” said Levy.

The study was published in the journal Nano Letters.

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