Optical nanomotors: Tiny 'motors' are driven by light

Now, a team at MIT and elsewhere has pushed through

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another boundary in the quest for such exotic contraptions, by creating in simulations the first system in which particles—ranging from roughly molecule- to bacteria-sized—can be manipulated by a beam of ordinary light rather than the expensive specialized light sources required by other systems. The findings are reported today in the journal Science Advances, by MIT postdocs Ognjen Ilic PhD '15, Ido Kaminer, and Bo Zhen; professor of physics Marin Soljacic; and two others.

Most research that attempts to manipulate matter with light, whether by pushing away individual atoms or small particles, attracting them, or spinning them around, involves the use of sophisticated laser beams or other specialized equipment that severely limits the kinds of uses of such systems can be applied to. "Our approach is to look at whether we can get all these interesting mechanical effects, but with very simple light," Ilic says.

The team decided to work on engineering the particles themselves, rather than the light beams, to get them to respond to ordinary light in particular ways. As their initial test, the researchers created simulated asymmetrical particles, called Janus (two-faced) particles, just a micrometer in diameter—one-hundredth the width of a human hair. These tiny spheres were composed of a silica core coated on side with a thin layer of gold.

Read more at: https://phys.org/news/2017-06-optical-nanomotors-tiny-motors-driven.html#jCp