Photonic Crystal Bends Microwaves

In it, Lin explains how he and colleagues used a larger, simpler lattice to bend microwaves around 90-degree corners, within radii smaller than a wavelength, and with almost 100 percent transmission efficiency.

The achievement -- like turning a hippopotamus on a dime -- lays groundwork for more accurately directed, lighter-weight microwave communications. It also provides proof of principle that similar structures would be effective at the much shorter wavelengths of long-distance optical communications and, potentially, optical computing, by making possible far cheaper, smaller, more efficient electromagnetic wave containers and guides than any known.

These artificial lattices, known as photonic crystals, guide electromagnetic radiation by a method fundamentally different from traditional index-of-refraction techniques. Waves are trapped in column-like arrays that --when fabricated to appropriate dimensions -- reflect desirable wavelengths as mirrors do light. Transmission is achieved through use of deliberately added defects, which act as wave guides.

The microwave work, achieved in two dimensions, was a collaboration with Sandia researchers Edmond Chow and Vincent Hietala, and physicists Pierre Villeneuve and J.D. Joannopoulos of the Massachusetts Institute of Technology.

Sandia is a multiprogram U.S. Department of Energy laboratory, operated by a subsidiary of Lockheed Martin Corp. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major research and development responsibilities in national security, energy, and environmental technologies.