Sandia LabNews

Labs' photonic crystal bends microwaves around tight corner

On the heels of his July 16 Nature paper with Jim Fleming (1723) on their artificial silicon lattice that efficiently bends infrared light (Lab News, Sept. 11), principal researcher Shawn Lin (1712) strikes again in a paper in today’s (Oct. 9) issue of the journal Science. In it, Shawn, Edmond Chow (1712), and Vince Hietala (1716) explain how they used another lattice — this one made of alumina — to bend microwaves around 90-degree corners within radii smaller than a wavelength.

The achievement was accomplished with almost 100 percent efficiency in transmission.

These artificial lattices, known as photonic crystals, guide electromagnetic radiation such as infrared and microwaves by a method fundamentally different from traditional index-of-refraction techniques. Waves are trapped in artificially created column-like arrays that, 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 work, achieved in two dimensions, was a collaboration with physicists Pierre Villeneuve and J.D. Joannopoulos of the Massachusetts Institute of Technology.

Photonic crystals make possible cheaper, smaller, more efficient wave containers and guides than any known for optical communications, and may advance the day of optical computing.