Light manipulates particles to form a reflective surface
T.M. Grzegorczyk et al./Phys. Rev. Lett. 2014
A focused beam of green light has transformed 150 plastic beads into a functional mirror. The feat is the first step toward an ambitious goal: deploying lasers in space to assemble a cloud of dustlike particles into a giant telescope mirror.
“I think it’s really cool,” says Michael Burns, a laser physicist at Harvard’s Rowland Institute. “It demonstrates something that had only been discussed before.”
Most of the fundamental physics behind the idea of building space mirrors with lasers is solid, Burns says. Light provides a subtle push when it bounces off matter. It can also trap particles illuminated within a laser beam, which allows scientists to isolate individual cells and even atoms. Finally, light scattering off a particle can serve as a bonding force, enabling multiple particles to self-assemble into organized structures. Exploiting these properties of light, astronomer Antoine Labeyrie proposed in 1979 that a pair of