Optical lift

The ability of light to apply pressure to objects is known as radiation pressure, which was first postulated in 1619 and proven in 1900. This is the principle behind the solar sail, which uses light radiation pressure to move through space. A 2010 study by physicist Grover Swartzlander and colleagues of the Rochester Institute of Technology in Rochester, New York shows light is also capable of creating the more complex force of "lift", which is the force generated by airfoils that make an airplane rise upwards as it travels forward. This study was published in December 2010 in Nature Photonics journal. Swartzlander predicted, observed and experimentally verified at a micrometer-scale that when applying a beam of laser light to a semi-cylindrical refractive rod, it automatically torques into a stable angle of attack, and then exhibits uniform motion. In optical lift, created by a "lightfoil", the lift is created within the transparent object as light shines through it and is refracted by its inner surfaces. In the lightfoil rods a greater proportion of light leaves in a direction perpendicular to the beam and this side therefore experiences a larger radiation pressure and hence, lift. == Potential uses ==

The 2010 discovery of stable optical lift is considered by some physicists to be "most surprising". a form of spacecraft propulsion for interstellar space travel. Solar sails are generally designed to harness light to "push" a spacecraft, whereas Swartzlander designed their lightfoil to lift in a perpendicular direction; this is where the idea of being able to steer a future solar sail spacecraft may be applied. Swartzlander said the next step would be to test lightfoils in air and experiment with a variety of materials with different refractive properties, and with incoherent light. ==See also==