A new nanolaser, with a design inspired by nature, can change color using the same nanomechanics that a chameleon uses. A chameleon changes color by controlling the spacing of nanocrystals on its skin. The nanolaser exploits periodic arrays of metal nanoparticles on a stretchable, polymer matrix in a similar way. As the matrix either stretches to pull the nanoparticles farther apart or contracts to push them closer together, the wavelength of the laser changes, which in turn changes the color of light it emits. A new nanolaser leverages the same color-changing mechanism that a chameleon uses to camouflage its skin. Courtesy of Egor Kamelev. “Hence, by stretching and releasing the elastomer substrate, we could select the emission color at will,” said Northwestern University professor Teri W. Odom. The nanolaser preserves its high mode quality by using hybrid quadrupole plasmons as an optical feedback mechanism. By increasing the size of the metal nanoparticles in the array, researchers from Northwestern University introduced ultrasharp lattice plasmon resonances with out-of-plane charge oscillations that were tolerant to lateral strain. Researchers performed semiquantum modeling to demonstrate that lasing buildup occurred at the hybrid quadrupole electromagnetic hot spots, to allow mechanical modulation of light-matter interactions on the nanoscale. Image courtesy of George Lebada. By patterning the metal nanoparticles onto an elastomeric slab surrounded by liquid gain, researchers achieved reversible, tunable nanolasing with high strain sensitivity. The nanolaser’s color-changing capabilities, along with these properties, could support advances in flexible optical displays in smartphones and televisions, wearable photonic devices, and ultrasensitive sensors that measure strain. The research was published in Nano Letters (doi:10.1021/acs.nanolett.8b01774).