 |
| Image Credit: Greg Williams / Wikiworld |
David Ruffner wasn't thinking about tractor beams-- until NASA called.
Last year, a team of researchers at NASA set out to work with scientists to develop a beam of light that could draw objects back along its length. Affixed to a space-probe, the tractor beam would remotely collect extraterrestrial atmospheric and planetary particles and transport them back to the space-probe for analysis. Now, scientists at New York University have put science-fiction into practice with a device that can pull particles of sand, plastic, and even molecules and cells up a conveyor belt of light.
David Grier is an optical and soft condensed matter physicist at New York University and an expert on the forces that light can exert on matter. When NASA called, he and his graduate student, David Ruffner, decided to tackle a tractor beam technique that was recently proposed by theoretical physicists, but never demonstrated in the laboratory.
When you shine a laser pointer at a slide, it forms a little spot. The tractor beam that Grier and Ruffner pursued used a beam that forms a bulls eye instead of a spot. The beam is called a Bessel beam.
Last year, a team of researchers at NASA set out to work with scientists to develop a beam of light that could draw objects back along its length. Affixed to a space-probe, the tractor beam would remotely collect extraterrestrial atmospheric and planetary particles and transport them back to the space-probe for analysis. Now, scientists at New York University have put science-fiction into practice with a device that can pull particles of sand, plastic, and even molecules and cells up a conveyor belt of light.
David Grier is an optical and soft condensed matter physicist at New York University and an expert on the forces that light can exert on matter. When NASA called, he and his graduate student, David Ruffner, decided to tackle a tractor beam technique that was recently proposed by theoretical physicists, but never demonstrated in the laboratory.
When you shine a laser pointer at a slide, it forms a little spot. The tractor beam that Grier and Ruffner pursued used a beam that forms a bulls eye instead of a spot. The beam is called a Bessel beam.
