Broadband Transformational Optics Lens, Described in "Applied Physics Letters," May Lead to Antenna Dishes that are Flat or Conform to Any Surface
By depositing an array of tiny, metallic, U-shaped structures onto a dielectric material, a team of researchers in China has created a new artificial surface that can bend and focus electromagnetic waves the same way an antenna does.
T.J. Cui/Southeast University Nanjing
CAPTION The prototype of the fabricated metasurface lens shown with simulated x components of electric fields at 9 GHz with the source placed at the bottom left, right and center of the lens.
This breakthrough, which the team is calling the first broadband transformation optics metasurface lens, may lead to the creation of new types of antennas that are flat, ultra low-profile or conformal to the shape of curved surfaces.
The new lens, described in AIP Publishing's journal Applied Physics Letters, was fabricated by Tie Jun Cui and colleagues at Southeast University in Nanjing, China and is an example of a metasurface or metamaterial -- an artificial material engineered in the lab that has properties not found in nature. In this case, by coating the surface with the tiny U-shaped elements, it acquires properties that mimic something known as a Luneburg lens.
First discovered in the 1940s Luneburg lenses are traditionally spherical optics that interact with light in an unusual way. Most lenses are made of a single material like plastic or glass that bends light passing through in a consistent, characteristic way -- a key characteristic of the material, which is called its "index of refraction." Some materials, like glass, have a higher index of refraction and bend light more than other materials -- such as quartz.
A Luneburg lens has the unusual property of bending light more or less depending on where the light strikes the lens. This is because in a Luneburg lens, the index of refraction varies across the spherical lens body, making it very different than a normal lens. Luneburg lenses can focus light or incoming electromagnetic waves to an off-axis point at the edge of the lens (not directly in front or behind it as a normal lens would do). Or they can uniformly channel electromagnetic waves emanating from a nearby point source and radiate them in a single direction -- something no spherical lens can do.
Because of their properties, Luneburg lenses find a variety of applications as radar reflectors and microwave antennae. However, the spherical shape of a typical Luneburg lens is inconvenience in some applications, Cui said, which is why he and his colleagues used inhomogeneous artificial structures to create a flat surface that acts like a Luneburg lens.
The new work compliments the traditional way of constructing Luneburg lenses based on geometric optics -- as well as a second way discovered in the last few years that uses holographic optics.
"We now have three systematical designing methods to manipulate the surface waves with inhomogeneous metasurfaces, the geometric optics, holographic optics, and transformation optics," Cui said. "These technologies can be combined to exploit more complicated applications."
The article, "A broadband transformation-optics metasurface lens" by Xiang Wan, Wei Xiang Jiang, Hui Feng Ma, and Tie Jun Cui appears on the cover of the journal Applied Physics Letters on April 14, 2014 (DOI: 10.1063/1.4870809). After that date it can be accessed at: http://scitation.aip.org/content/aip/apl/104/15/10.1063/1.4870809
ABOUT THE JOURNAL
Applied Physics Letters features concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology. See: http://apl.aip.org
Jason Socrates Bardi | newswise
Clandestine black hole may represent new population
28.06.2016 | International Centre for Radio Astronomy Research
Rotating ring of complex organic molecules discovered around newborn star
28.06.2016 | National Institutes of Natural Sciences
R2D2, a joint project to analyze and development high-TRL processes and technologies for manufacture of flexible organic light-emitting diodes (OLEDs) funded by the German Federal Ministry of Education and Research (BMBF) has been successfully completed.
In contrast to point light sources like LEDs made of inorganic semiconductor crystals, organic light-emitting diodes (OLEDs) are light-emitting surfaces. Their...
High resolution rotational spectroscopy reveals an unprecedented number of conformations of an odorant molecule – a new world record!
In a recent publication in the journal Physical Chemistry Chemical Physics, researchers from the Max Planck Institute for the Structure and Dynamics of Matter...
Strands of cow cartilage substitute for ink in a 3D bioprinting process that may one day create cartilage patches for worn out joints, according to a team of engineers. "Our goal is to create tissue that can be used to replace large amounts of worn out tissue or design patches," said Ibrahim T. Ozbolat, associate professor of engineering science and mechanics. "Those who have osteoarthritis in their joints suffer a lot. We need a new alternative treatment for this."
Cartilage is a good tissue to target for scale-up bioprinting because it is made up of only one cell type and has no blood vessels within the tissue. It is...
Physicists in Innsbruck have realized the first quantum simulation of lattice gauge theories, building a bridge between high-energy theory and atomic physics. In the journal Nature, Rainer Blatt‘s and Peter Zoller’s research teams describe how they simulated the creation of elementary particle pairs out of the vacuum by using a quantum computer.
Elementary particles are the fundamental buildings blocks of matter, and their properties are described by the Standard Model of particle physics. The...
A year and a half on the outer wall of the International Space Station ISS in altitude of 400 kilometers is a real challenge. Whether a primordial bacterium...
28.06.2016 | Event News
09.06.2016 | Event News
24.05.2016 | Event News
28.06.2016 | Physics and Astronomy
28.06.2016 | Life Sciences
28.06.2016 | Physics and Astronomy