Chameleons are able to change color via a layer of skin cells known as iridophores, which contain nanocrystals. As the lizards stretch or relax their skin, the spacing between those crystals changes, altering the manner in which they reflect light. Now, scientists have designed a color-changing nanolaser that works the same way.

Led by Prof. Teri W. Odom (who previously developed a liquid-dye-based color-changing nanolaser), a team at Illinois' Northwestern University created a flat elastomer sheet composed of a stretchable polymer covered with metal nanoparticles. A laser beam is projected onto that sheet, reflecting off the particles.

As the sheet is stretched or compressed, the spacing between the particles increases or decreases. This alters the wavelength of the reflected laser beam, causing its perceived color to change accordingly. "Hence, by stretching and releasing the elastomer substrate, we could select the emission color at will," says Odom.

According to the university, the laser device is robust, tuneable, reversible and highly sensitive to strain. It could ultimately find use in applications such as flexible smartphone and TV displays, wearable photonic devices, and ultra-sensitive sensors that change color to indicate mechanical strain.

The research is described in a paper that was published this Tuesday in the journal Nano Letters.