Superman's ability to shoot laser beams from his eyes has come a step closer to reality, thanks to scientists who have developed an ultra-thin membrane laser using organic semiconductors. These ocular lasers could be harnessed for new applications in security, biophotonics and photomedicine, according to researchers from the University of St Andrews in the UK. Published in the journal Nature Communications, the research explains that the threshold of the membrane lasers is compatible with the requirements for safe operation in the human eye.
The team was also able to demonstrate ocular lasing using the cow eye as a model system. The new laser approaches the fundamental limit in specific weight and thickness, as well as an exceptional mechanical flexibility, which allows to put them on a contact lens or a bank note. "In ancient Greece, Plato believed that visual perception is mediated by 'eye beams' - beams actively sent out by the eyes to probe the environment," said Malte Gather, a professor at the University of St Andrews.
"Plato's emission theory has of course long been refuted, but superheroes with lasers in their eyes live on in popular culture and comic books," said Gather. "Our work represents a new milestone in laser development and, in particular, points the way to how lasers can be used in inherently soft and ductile environments, be it in wearable sensors or as an authentication feature on bank notes," Gather said.
By floating a thin plastic film off a substrate we have made some of the world's smallest and lightest lasers and put them on contact lenses and bank notes, said Ifor Samuel from University of St Andrews.
The team also demonstrated that the devices were flexible and mechanically robust, even when attached to another object, and that their optical properties did not change over the course of several months.
They were then able to stick these ultra-thin lasers onto banknotes and contact lenses, where they suggest the devices could be used as flexible and wearable security tags. "By varying the materials and adjusting the grating structures of the laser, the emission can be designed to show a specific series of sharp lines on a flat background - the ones and zeros of a digital barcode," said Markus Karl, who worked on the new lasers as part of his PhD.
