AOM Reaches Unprecedented Speeds

A new acousto-optic modulator can steer laser beams at unprecedented speeds, potentially enabling finer light control for microscopy and other applications.

The device features a liquid-filled cavity surrounded by a cylindrical ultrasound transducer made of 64 piezoelectric elements. A team of British researchers used the device to convert a Gaussian laser beam into a Bessel beam with tunable order and position.

The new acousto-optical modulator can make millions of adjustments to a laser beam’s shape every second. Courtesy of the universities of Bristol and Dundee.

“Previous attempts to do this have not had the level of sophistication that we have achieved in the control of our acoustic fields, which has given us much greater flexibility in the control we have over light with these devices,” said biophotonics lecturer Dr. Mike MacDonald of the University of Dundee in Scotland.

MacDonald said the device works more quickly than existing spatial light modulators and allows higher laser powers.

“This reconfigurability can happen extremely fast, limited only by the speed of the sound waves,” said University of Bristol ultrasonics professor Dr. Bruce Drinkwater. “The key advantage of this method is that it potentially offers very high refresh rates — millions of refreshes per second is now possible.”

The technique could enable reconfigurable microscope lenses that can automatically compensate for optical aberrations, as well as a new generation of rapidly reconfigurable optical tweezers. Other applications may include beam shaping for laser materials processing and free-space optical communications.

The research was published in Optics Express (doi: 10.1364/OE.23.000026 [open access]).

For more information, visit www.bristol.ac.uk.