Silicon photonic crystals key to optical cloaking
In computer simulations, the researchers have demonstrated an approximate cloaking effect created by concentric rings of silicon photonic crystals. The mathematical proof brings scientists a step closer to a practical solution for optical cloaking.
"This is much more than a theoretical exercise," said Harley Johnson, a Cannon Faculty Scholar and professor of mechanical science and engineering at Illinois. "An optical cloaking device is almost within reach."
In October 2006, an invisibility cloak operating in the microwave region of the electromagnetic spectrum was reported by researchers at Duke University, Imperial College in London, and Sensor Metrix in San Diego. In their experimental demonstration, microwave cloaking was achieved through a thin coating containing an array of tiny metallic structures called ring resonators.
To perform the same feat at much smaller wavelengths in the visible portion of the spectrum, however, would require ring resonators smaller than ...