Light can lift a wing-shaped refractive object, in a concept comparable to aerodynamic lift reports a paper published online this week in Nature Photonics. The work will not only advance the control of microscopic particle transportation in liquids, but could potentially aid the design of solar sails for interstellar space travel.
Grover Swartzlander and co-workers found that a micrometre-scale object with differently shaped top and bottom surfaces experiences a transverse lift when illuminated by a uniform milliwatt-scale stream of light. Unlike aerodynamic lift, which is based on a pressure difference, this ‘lightfoil’ technique relies on refraction pressure resulting from a difference in the refracted and reflected rays of light.
The researchers achieved uniform motion of a few micrometres per second, and foresee that this technique could be extended to the macroscopic domain.