A laser in the form of a flexible and lightweight membrane can be affixed to objects as diverse as banknotes, contact lenses and fingernails.
Although engineers can easily make stretchy, bendable light-emitting diodes from carbon-based polymers, early polymer lasers have tended to be rigid and bulky, partly because they require a flat, thick support surface. Malte Gather and his colleagues at the University of St Andrews, UK, devised a flexible polymer laser less than one micrometre thick. The researchers then lifted this ‘membrane’ laser off its supporting substrate and transferred it onto a new surface. An external source provides power to the device.
The resulting laser can be tuned to emit light in a unique combination of wavelengths, making it useful as a barcode-like security label. Such laser tags could make it more difficult to counterfeit banknotes and could help in authenticating identification documents, the authors say.