Slow Light Slowed Even More

New nanomaterials that allow different wavelengths of light to be trapped have the potential to boost data storage communications.

Qiaoqiang Gan, an assistant professor of electrical engineering at the University at Buffalo's School of Engineering and Applied Sciences, and his colleagues at Lehigh University described how they slowed broadband lightwaves using material called nanoplasmonic structures.

Gan said that the ultimate goal is to achieve a breakthrough in optical communications called multiplexed, multiwavelength communications, where optical data can potentially be tamed at different wavelengths, thus greatly increasing processing and transmission capacity.

He notes that it is widely recognized that if light could ever be stopped entirely, new possibilities would open up for data storage.

New nanomaterials created by Qiaoqiang Gan allow for the trapping of different wavelengths of light, which could boost data storage and communications. (Image: Douglas Levere, UB Communications)

"At the moment, processing data with optical signals is limited by how quickly the signal can be interpreted," he said. "If the signal can be slowed, more information could be processed without overloading the system."

They created the nanoplasmonic structures by making nanoscale grooves in metallic surfaces at different depths, altering the materials' optical properties.

Those properties allow various wavelengths of light to be trapped at different positions in the structure, potentially allowing for optical data storage and enhanced nonlinear optics.

The structures Gan developed slow light down so much that they can trap multiple wavelengths of light on a single chip, whereas conventional methods can trap only a single wavelength in a narrow band.

"Light is usually very fast, but the structures I created can slow broadband light significantly," said Gan. "It's as though I can hold the light in my hand."

Gan and his colleagues also found that because the nanoplasmonic structures they developed can trap very slow resonances of light, they can do so at room temperature, instead of at the ultracold temperatures that are required in conventional slow-light technologies.

So far they have trapped red to green light. Now they are working on trapping a broader wavelength, from red to blue, and eventually hope to trap the entire rainbow.

For more information, visit: www.buffalo.edu