Scientists have designed a nanolaser that can change colour in the same the way that chameleons are able to change the colour of their skin. Scientists at Northwestern University believe the work could open the door for advances in flexible optical displays in smartphones and flat panel displays, wearable devices and sensors that measure strain.
“Chameleons can easily change their colours by controlling the spacing among the nanocrystals on their
skin, which determines the colour we observe,” said Teri Odom, professor of chemistry in Northwestern’s Weinberg College
of Arts and Sciences. “This colouring based on surface structure is chemically stable and robust.”
The
research was published online in the
journal Nano Letters.
The same way a chameleon controls
the spacing of nanocrystals on its skin, the Northwestern team’s laser exploits periodic arrays of metal nanoparticles
on a stretchable, polymer matrix. As the matrix either stretches to pull the nanoparticles farther apart
or contracts to push them closer together, the wavelength emitted from the laser changes wavelength, which
also changes its colour.
The resulting laser is robust, tunable, reversible and has a high sensitivity to
strain. These properties are critical for applications in responsive optical displays, on-chip photonic circuits and multiplexed optical communication.