Optical lifting demonstrated for the first time w Video

center_img Explore further Citation: Optical lifting demonstrated for the first time (w/ Video) (2010, December 7) retrieved 18 August 2019 from https://phys.org/news/2010-12-optical-video.html Time-lapsed composite image (1.67 s per shot) of a semi-cylindrical rod lifting sideways from left to right near the bottom of a glass chamber, as a result of a transverse optical lift force. Image credit: Nature Photonics, doi:10.1038/nphoton.2010.266 Light has been known for some time to be capable of pushing objects and this is the principle behind the solar sail, which uses light to push vehicles along in space. Now, a new study by physicist Dr. Grover Swatzlander 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 a plane rise upwards as it travels forward.In a paper that appeared online in Nature Photonics on December 5th, Swartzlander and colleagues describe their demonstration of light providing optical lift to tiny lightfoils. The experiment began as computer models that suggested when light is shone on tiny objects shaped like a wing a stable lift force would be created. Intrigued, the researchers decided to do physical experiments in the laboratory, and they created tiny, transparent, micrometer-sized rods that were flat on one side and rounded on the other, rather like airplane wings. They immersed the lighfoils in water and bombarded them with 130 mW ultraviolet laser light from underneath the chamber. As predicted, the lightfoils were pushed upwards by the light, but they also moved sideways in a direction perpendicular to the beam of light, in other words they were optically lifted. Symmetrical micro-spheres did not show the optical lift effect.In aerodynamic lift, which is created by an airfoil, the lift occurs because the wing shape causes air flowing under the wing to move more slowly and at higher pressure than that above the wing. 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. © 2010 PhysOrg.com Play Videos: Nature Photonics, doi:10.1038/nphoton.2010.266 last_img read more