Beijing, China (BBN)-Researchers in China have created a new artificial surface that can bend and focus electromagnetic waves just like an antenna.
This innovation may lead to the fabrication of flat, very low profile antennas that also could conform to the shape of curved surfaces, reports Science Recorder.
Tie Jun Cui and his colleagues at Southeast University in Nanjing, China, are calling their breakthrough the “first broadband transformation optics metasurface lens,” according to a statement published in Eureka Alert.
The team’s findings are published in the April 14 issue of the journal Applied Physics Letters.
By placing an array of very tiny, metallic, U-shaped structures onto a dielectric material, the researchers created a lens with properties not found in nature.
In the process, the metasurface acquired the properties of something called a Luneberg lens.
First developed in the 1940s, the Luneberg lens is a traditionally spherical lens that interacts with light in an unusual way.
Most lenses are made of a single uniform material, such as plastic or glass, that bends light passing through it in a predictable, consistent way according to its index of refraction, which varies according to the material of which it is made.
Glass, for example, has a higher index of refraction than quartz.
But Luneberg lenses have a refractive index that varies across the spherical lens body because it has the unusual property of bending light more or less depending on where light hits the lens.
This is the result of the lens’s ability to focus incoming electromagnetic waves to an off-axis point at the edge of the lens–not directly in front or in back of it as a normal lens would do, the statement said.
In addition, Luneberg lenses can uniformly channel light waves coming from a nearby source and radiate them in a particular direction, a feat no normal lenses can do.
The only problem with the Luneberg lens was that its spherical shape limited its applications. Therefore, the study says, the goal was to create a lens that would be flat and still have all the properties of a Luneberg lens.
“We now have three systematic designing methods to manipulate the surface waves with inhomogeneous metasurfaces, the geometric optics, the holographic optics, and transformation optics,” said Dr Cui in a statement. “These technologies can be combined to exploit more complicated applications.”
BBN/ANS/AD/16Aprp14-6:35 pm (BST)
