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131:, but the excitement came when the particles were forced to the side in a direction perpendicular to the direction of propagating light. The transverse force on the particles is the lift force. The researchers discovered not only that the rods experienced stable lift, but that, depending on refractive index, the rod could have up to two stable angles of attack it rotated to when exposed to the laser light. Symmetrical spheres tested did not exhibit this same lift effect.
119:, a stable lift force is applied to the particle. Then 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 lightfoils in water and bombarded them with 130 mW
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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.
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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.
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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.
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refractive object with differently shaped top and bottom surfaces experiences a stable transverse lift force when placed in a uniform stream of
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Swartzlander Jr, Grover A.; Timothy J. Peterson; Alexandra B. Artusio-Glimpse & Alan D. Raisanen (5 December 2010). "Stable optical lift".
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journal. Swartzlander predicted, observed and experimentally verified at a micrometer-scale that when applying a beam of
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The 2010 discovery of stable optical lift is considered by some physicists to be "most surprising". Unlike
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Video: Optical lifting demonstrated for the first time
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