Researchers at the University of California, Berkeley have made a breakthrough by creating a small gold “light mill.” Although inspired by the windmill, this new tetra-gammadion shaped light mill made from gold works very differently. Unlike the blades of a windmill that are tilted to channel the physical impact of air into angular movement in one direction, the light mill’s blades are completely flat and can rotate either clockwise or counterclockwise.
Said to be the smallest motor ever, the light mill measures just 200 nanometers in diameter. The researchers claim that at 2 specific wavelengths of light, 810 nanometers and 1,700 nanometers, the blades of the light mill is bent, twisted one direction or another, just like a windmill. These tiny little devices could be used for winding DNA, actuators for nanoelectromechanical systems and solar energy harvesting.