Researchers from the University of St Andrews have developed a flexible and ultra-thin membrane-based organic laser that can shoot out a beam of photons while embedded in a contact lens.
But before anyone gets carried away with ideas of cutting through walls à la Cyclops from X-Men, we must note that is not quite how this form of laser technology works.
The team’s “optically pumped” organic laser uses a semiconductive polymer that is excited by exposure to light – in this case, blue light – and subsequently emits a narrow band of light in the visible spectrum that can be tuned to carry binary coded information; essentially, the visual version of a barcode.
In recent years, engineers have revolutionized the field of optoelectronics – electronic devices that manipulate light – by adopting organic polymers as semiconductors. Yet organic lasers, which have the potential to drive new data communications technology and chemical detection devices, have been restricted by the need for rigid backing material.
As described in the journal Nature Communications, the St Andrews physicists invented a new process wherein the laser’s organic semiconductor polymer and diffraction grating are printed into the correct configuration onto a piece of glass, then subsequently freed by submerging the whole assemblage in a water bath.
“The resulting 200-nm thick membrane lasers were operated freestanding in air or readily transferred onto a new substrate, on which direct fabrication of a laser may otherwise be impossible or impractical,” the authors wrote.
Hoping to demonstrate the functionality and versatility of their breakthrough membrane lasers, the authors picked two of the most exciting applications: security stickers for bank notes and wearable identification tags.
Two hundred days after placing a laser sticker on the transparent window of a £5 bill, the correct security signature was still being transmitted in response to light, showing "how membrane lasers that were designed to produce a well-defined and unique lasing spectrum can be used as counterfeit-resilient, barcode-type security labels on bank notes.”