They said it could be done and now they've done it. What's more, they did it with a GRIN. A team of researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley, have carried out the first experimental demonstration of GRIN for gradient index plasmonics, a hybrid technology that opens the door to a wide range of exotic optics, including superfast computers based on light rather than electronic signals, ultra-powerful optical microscopes able to resolve DNA molecules with visible light, and "invisibility" carpet-cloaking devices.
Working with composites featuring a dielectric (non-conducting) material on a metal substrate, and "grey-scale" electron beam lithography, a standard method in the computer chip industry for patterning 3-D surface topographies, the researchers have fabricated highly efficient plasmonic versions of Luneburg and Eaton lenses. A Luneburg lens focuses light from all directions equally well, and an Eaton lens bends light 90 degrees from all incoming directions.
"This past year, we used computer simulations to demonstrate that with only moderate modifications of an isotropic dielectric material in a dielectric-metal composite, it would be possible to achieve practical transformation optics results," says Xiang Zhang, who led this research. "Our GRIN plasmonics technique provides a practical way for routing light at very small scales and producing efficient functional plasmonic devices."
Zhang, a principal investigator with Berkeley Lab's Materials Sciences Division and director of UC Berkeley's Nano-scale Science and Engineering Center (SINAM), is the corresponding author of a paper in the journal Nature Nanotechnology, describing this work titled, "Plasmonic Luneburg and Eaton Lenses." Co-authoring the paper were Thomas Zentgraf, Yongmin Liu, Maiken Mikkelsen and Jason Valentine.
GRIN plasmonics combines met
|Contact: Lynn Yarris|
DOE/Lawrence Berkeley National Laboratory