Engineers working in optical communications bear more than a passing resemblance to dreamers chasing rainbows.
They may not wish literally to capture all the colors of the spectrum, but they do seek to control the rate at which light from across the spectrum moves through optical circuits.
This pursuit is daunting when those circuits contain dimensions measured in nanometers.
At the nanoscale, says Qiaoqiang Gan, a Ph.D. candidate in electrical engineering at Lehigh University in Bethlehem, Pa., engineers hoping to integrate optical structures with electronic chips face a dilemma.
Light waves transmit data with greater speed and control than do electrical signals, which are hindered by the mobility of the electrons in semiconducting materials.
But light is more difficult to control at the nanoscale because of natural limits on its diffraction, or ability to resolve.
"There is a mismatch between nanoelectronics and nanophotonics," says Gan. "Because of the diffraction limit of light, optical circuits are now much larger than their electronic counterparts. This poses an obstacle to the integration of optical structures with electrical devices.
"For that reason, the dream now among photonics researchers is to make optical structures as small as possible and integrate them with electrical devices."
Gan and his colleagues have made a major contribution towards this effort by developing a relatively simple structure that can slow down or even stop light waves over a wide portion of the light spectrum.
On Friday, June 27, they published an article describing their progress in Physical Review Letters (PRL), a publication of the American Physical Society. PRL is one of the most influential international journals devoted to basic physics.
The article, titled "Ultrawide-Bandwidth Slow-Light System Based on THz Plasmonic Graded Metallic Grating Structures," is coauthored by Gan
|Contact: Kurt Pfitzer|