A new wrinkle in the control of waves

Flexible materials could provide ways to manipulate sound and light. Flexible, layered materials textured with nanoscale wrinkles could provide a new way of controlling the wavelengths and distribution of waves, whether of sound or light. The new method, developed by researchers at MIT, could eventually find applications from nondestructive testing of materials to sound suppression, and could also provide new insights into soft biological systems and possibly lead to new diagnostic tools. The findings are described in a paper published this week in the journal Physical Review Letters , written by MIT postdoc Stephan Rudykh and Mary Boyce, a former professor of mechanical engineering at MIT who is now dean of the Fu Foundation School of Engineering and Applied Science at Columbia University. While materials' properties are known to affect the propagation of light and sound, in most cases these properties are fixed when the material is made or grown, and are difficult to alter later. But in these layered materials, changing the properties - for example, to "tune" a material to filter out specific colors of light - can be as simple as stretching the flexible material. "These effects are highly tunable, reversible, and controllable," Rudykh says.