Phil Marston | CAS in the Media | Washington State University

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Scientists Invent a Tractor Beam Made of Sound

November 4, 2015

Scientists have long been able to levitate small objects, like drops of water or plastic pellets, using only the power of sound. By sandwiching an object between two sets of speakers—or a speaker and a reflector—you can send precise, energetic blasts of ultrasonic noise to trap objects midair. But today, a fascinating new breakthrough can now accomplish this odd feat of levitation with a single array of speakers on just one side. It’s like using sonic tongs with just one side instead of two. » More …

Physicists sound-out acoustic tractor beam

May 23, 2014

First proposed in 2006 by Philip Marstonof Washington State University and realized using light in 2010 by David Grier and colleagues at New York University, the technique involves firing two beams of ultrasonic waves upwards at a triangular-shaped target at about 51° either side from the vertical direction.

The tractor beam has arrived

August 6, 2013

Phil Marston. Photo credit Robert Hubner — Phil Marston. Photo by Robert Hubner.

WSU physicist Phil Marston was intrigued by the way an acoustic beam is scattered by a sphere.

“Basically, it goes into the category of a problem you solve because it would be curious to see what the answer is and whether there is something there that you didn’t anticipate,” he says. “That was true.”

In the serpentine path from abstract musing to basic science to demonstrated phenomenon, he sowed the seeds for a small-scale but real-life tractor beam that could have applications in both nanotechnology and medicine.