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| An artist's impression of a Bessel beam emerging from the acousto-optic device built by researchers at the University of Bristol and the University of Dundee. (Courtesy: Universities of Bristol and Dundee) |
Topics: Acoustic Physics, Brownian Motion, Laser, Optical Tweezers
A new way to create and guide beams of "twisted light" has been created by researchers in the UK. The team used a cylindrical array of ultrasound loudspeakers to create a pattern of density waves in a fluid through which a laser beam is shone. The system creates twisted "Bessel beams" that can be reconfigured at a rate of about 150 kHz and shows promise for use in a wide range of applications including optical tweezers, high-speed data transmission and aberration correction for microscopes.
Twisted light refers to a beam with a wavefront that rotates around its direction of propagation with a corkscrew-like motion – and therefore carries orbital angular momentum. Bessel beams are a type of twisted light that have been created in the lab using special lenses and have been used in optical tweezers. An important feature of Bessel beams is that they do not diverge as they propagate, which makes them well-suited for optical tweezers.
Physics World: Ultrasound puts a new twist on light, Hamish Johnston
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