Nanolaser changes color when stretched

Inspired by a chameleon’s prowess, researchers have made a tiny laser that changes color as it is stretched and released (Nano Lett. 2018, DOI: 10.1021/acs.nanolett.8b01774). The nanolaser is 10 times as sensitive as previous stretchable nanolasers, providing a slightly greater change in wavelength with only one-tenth the stretching. The tunable system could be used in flexible displays, wearable sensors, and lab-on-a-chip devices. Teri W. Odom, George C. Schatz, and their colleagues at Northwestern University deposited an array of cylindrical, 260-nm-wide gold nanoparticles on a polydimethyl­siloxane sheet. They surrounded the nanoparticles with a liquid gain material, a dye solution that amplifies light to achieve lasing. When stimulated with a light source, the nanolaser emits near-infrared light at around 870 nm. The emission wavelength increases, shifting farther into the infrared, when the device is stretched and goes back to the original wavelength when released. Tweaking the type of dye and the nanoparticle spacing could give a wide range of emitted laser light colors, Odom says.