Researchers from the University of California at Berkeley have created a thin, chameleon-like material that can be made to change color — on demand — by applying a minute amount of force.

The new material offers possibilities for display technologies, color-shifting camouflage, and sensors that can detect otherwise imperceptible defects in buildings, bridges, and aircraft.

By etching tiny features — smaller than a wavelength of light — onto a silicon film one thousand times thinner than a human hair, the researchers were able to select the range of colors the material would reflect, depending on how it was flexed and bent.

The researchers formed grating bars using a semiconductor layer of silicon approximately 120-nm thick. Silicon bars were then embedded into a flexible layer of silicone. As the silicone was bent or flexed, the period of the grating spacings responded in kind.

The semiconductor technology produces materials that reflect up to 83% of the incoming light.

The initial design created colors across a 39-nm range of wavelengths. Future designs, the researchers believe, could cover a wider range of colors and reflect light with even greater efficiency.


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