Physicists have created a mirror by using a laser to herd tiny particles into a continuous reflective surface.

Credit: T. M. GRZEGORCZYK (BAE SYSTEMS/MIT)/J. ROHNER/J.-M. FOURNIER (EPFL)

Optical forces from laser beams have already been used to manipulate single particles. Now, Tomasz Grzegorczyk at BAE Systems in Burlington, Massachusetts, and his colleagues have used a green laser to organize about 150 polystyrene spheres suspended in water. The three-micrometre-wide beads interacted with each other to form a crystal-like membrane configuration (pictured), and a camera was used to capture an image reflected off the membrane surface.

The method gives the membrane self-healing properties, and one day could be used to build ultralight mirrors with a large surface area for space telescopes, the authors suggest.

Phys. Rev. Lett. 112, 023902 (2014)