Oulton had been working on combining plasmonics and semiconductors, where these losses are even more pronounced, when he came up with an idea to achieve simultaneously strong confinement of the light and mitigate the losses. His theoretical "hybrid" optical fiber consists of a very thin semiconductor wire placed close to a smooth sheet of silver.
"It's really a very simple geometry, and I was surprised that no one had come up with it before," Oulton said.
Oulton ran computer simulations to test this idea. He found that not only could the light compress into spaces only tens of nanometers wide, but it could travel distances nearly 100 times greater in the simulation than by conventional surface plasmonics alone. Instead of the light moving down the center of the thin wire, as the wire approaches the metal sheet, light waves are trapped in the gap between them, the researchers found.
Oulton believes the hybrid technique of confining light could have huge ramifications. It brings light closer to the scale of electrons' wavelengths, meaning that new links between optical and electronic communications might be possible.
This idea could be an important step on the road to an optical computer, a machine where all electronics are replaced with optical parts, Oulton said. The construction of a compact optical transistor is currently a major stumbling block in the progress toward fully optical computing, and this technique for compacting light and linking plasmonics with semiconductors might help clear this hurdle, the researchers said.