A Laser-Powered Paper Plane

A laser-powered paper plane has been demonstrated by researchers in Japan (Takashi Yabe, Tokyo Institute of Technology, yabe@mech.titech.ac.jp). Advanced versions of such a plane could potentially monitor climate and volcanic eruptions from a bird's-eye view.

The researchers' "microplanes" have tiny dimensions (about an inch or two on a side), and very low masses (only 0.1 or 0.2 grams). Central to the design of each plane is a two-layer "target region ": either a water droplet or polymer (lucite) on a small aluminum-coated area.

To propel the plane, the target region is irradiated by a commercial-grade yttrium-aluminum-garnet (YAG) laser beam. Striking the aluminum surface behind the lucite or water, the laser beam creates a plasma that ejects the lucite or squirts out a water droplet, generating a thrust sufficient to give the plane a velocity of about 3 miles per hour.

Therefore, the plane works because of Newton's third law, in which an action (the aluminum plasma pushing the water or lucite) produces an equal and opposite reaction (a thrust on the plane). The researchers hope eventually to develop microplanes that can be continually guided by laser light. (Yabe et al., Applied Physics Letters, 10 June 2002.)