Ultra-small transducers produce ultra-high frequencies

This is the vision of Nottingham University scientists and engineers who have built ultrasonic transducers so small they are undetectable by the human eye.

The researchers claim the transducers are orders of magnitude smaller than current systems, adding that up to 500 of the smallest ones could be placed across the width of one human hair.

They can produce ultrasound of such a high frequency that its wavelength is smaller than that of visible light. Theoretically, they make it possible for ultrasonic images to take finer pictures than the most powerful optical microscopes.

Matt Clark, of the Applied Optics Group from the School of Electrical and Electronic Engineering at Nottingham University, explained this is because resolution, in optical or ultrasonic applications, is limited by wavelength.

‘The size of the smallest object you can see is directly proportional to the wavelength,’ he said. ‘With a large wavelength you can see big objects but not small objects. If you have a small wavelength you can see smaller and smaller things.