Physics

'Nanoear' hears small sounds

Journal name:
Nature
Volume:
481,
Page:
116
Date published:
DOI:
doi:10.1038/481116b
Published online

By using laser beams to trap a gold nanoparticle, researchers in Germany have developed a sensitive sound-wave detector.

Tightly focused laser beams, known as optical tweezers, have been used to manipulate microscopic objects for two decades. Andrey Lutich, Jochen Feldmann and their co-workers at the Ludwig–Maximilians University in Munich used a similar approach: they suspended a 60-nanometre gold nanoparticle in water in the focal spot of a laser beam. They sent sound waves through the water and measured changes in the particle's constrained motion. The authors calculate that the nanoparticle can pick up sounds as low as −60 decibels, making the set-up a million times more sensitive than the human ear.

Phys. Rev. Lett. 108, 018101 (2012)

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