A layer of tiny grains can slow sound waves
Monday, August 5, 2013 - 07:00
in Physics & Chemistry
In some ways, granular material—such as a pile of sand—can behave much like a crystal, with its close-packed grains mimicking the precise, orderly arrangement of crystalline atoms. Now researchers at MIT have pushed that similarity to a new limit, creating two-dimensional arrays of micrograins that can funnel acoustic waves, much as specially designed crystals can control the passage of light or other waves.