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The Register Lecture: How to build your own tractor beam

Bristol's Dr Asier Marzo on acoustic levitation

Levitation and tractor beams are the stuff of science fiction legend. Think Marty McFly’s hoverboard from Steven Spielberg’s Back to the Future II in 1989, or any number of Star Trek episodes.

The real-world application of such technology, however, has been limited by the size of the object you can control. Until now, as a group of lucky Reg readers found out at this Register Lecture on May 23.

Engineers at the University of Bristol recently demonstrated that it is possible to trap objects larger than the wavelength of a sound wave using an acoustic tractor beam.

They employed a rotating sound field using 40kHz ultrasonic waves – a pitch usually employed by bats - to suspend a 2cm polystyrene ball.

Dr Asier Marzo, one of the brains behind this breakthrough, joined us on May 23 and demonstrated the working principles of acoustic levitation and its applications and challenges. There were live demonstrations and the audience learned how to build their own levitators at home.

Dr Marzo is a research associate at the University of Bristol and a member of the department of mechanical engineering, ultrasonic and non-destructive testing. He has spoken and written widely on the topic of acoustic levitation and physics of trapping and controlling particles. ®

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