WEST LAFAYETTE, Ind. - Researchers have taken a step toward overcoming a key obstacle in commercializing "hyperbolic metamaterials," structures that could bring optical advances including ultrapowerful microscopes, computers and solar cells.
The researchers have shown how to create the metamaterials without the traditional silver or gold previously required, said Alexandra Boltasseva, a Purdue University assistant professor of electrical and computer engineering.
Using the metals is impractical for industry because of high cost and incompatibility with semiconductor manufacturing processes. The metals also do not transmit light efficiently, causing much of it to be lost. The Purdue researchers replaced the metals with an "aluminum-doped zinc oxide," or AZO.
"This means we can have a completely new material platform for creating optical metamaterials, which offers important advantages," Boltasseva said.
Doctoral student Gururaj V. Naik provided major contributions to the research, working with a team to develop a new metamaterial consisting of 16 layers alternating between AZO and zinc oxide. Light passing from the zinc oxide to the AZO layers encounters an "extreme anisotropy," causing its dispersion to become "hyperbolic," which dramatically changes the light's behavior.
"The doped oxide brings not only enhanced performance but also is compatible with semiconductors," Boltasseva said.
Research findings are detailed in a paper appearing Monday (May 14) in the Proceedings of the National Academy of Sciences.
The list of possible applications for metamaterials includes a "planar hyperlens" that could make optical microscopes 10 times more powerful and able to see objects as small as DNA; advanced sensors; more efficient solar collectors; quantum computing; and cloaking devices.
The AZO also makes it possible to "tune" the optical properties of metamaterials, an advance that could has
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