Resembling everything from brilliant round-cut diamonds to star-shaped snowflakes, Fibonacci-structured crystals inspired two U scientists to develop filters that could revolutionize the technological world.
Ajay Nahata, a U associate professor of electrical and computer engineering, and Z. Valentine Vardeny, a distinguished professor of physics, teamed up through the U’s synergy research program to explore the potential patterns these crystals create.
The two scientists recreated the patterns punching holes into stainless-steel foil. They then set about testing the diffusion of different light waves through the foil.
Terahertz falls in between gigahertz and X-ray wavelengths. Vardeny called it a “teenager,” because it fits into the middle of the spectrum and knowledge of its capacity is not fully developed.
Terahertz frequencies travel at 1,000 billion waves per second, as compared with gigahertz signals, which travel one billion waves per second.
By projecting low levels of terahertz frequencies through a foil filter and using a device to measure the output of light, they found almost all the transmission sent traveled through the filter.
“You could imagine with an object that is 80 percent metal that you would receive less transmission,” Nahata said. “We found that at certain frequencies it is possible to get almost 100 percent transmission.”
In the spectrum of light, there are many different levels-the majority cannot be seen by the naked eye.
When a crystal is X-rayed, the image produced has a structured and square-like pattern, known as periodic. In the ’80s, scientist Dan Shechtman discovered an anomaly-not all crystals comply with this pattern.
He coined them “quasicrystals” because they have distinct patterns. But if interrupted, the entire shape of the crystal is destroyed.
Until this study, such complete and rapid transmission has only been able to be achieved when crystal patterns were used.
Nahata and Vardeny said most technology operates with gigahertz signals, and the development of terahertz will change the speed at which today’s electronic devices function.
“This is an unexplored field, and (the research) is a starting point to make devices for the terahertz range,” Nahata said.
Nahata said he estimates that in the next decade wireless communication will begin making the shift to using terahertz because of its speed.
“People want to be able to transfer data at a faster rate; there is a non-stop need to send information at faster rates,” Nahata said
With development of technology using terahertz wavelengths, faster transmission of data is just around the corner, Nahata said.
The research Nahata and Vardeny conducted was published in the March edition of Nature magazine, and can be accessed online at www.nature.com/nature/journal/v446/n7135/full/nature05620.html.
Jeremy BigelowAmit Agrawal, a doctoral student in electrical and computer engineering, holds a 10-fold quasicrystal symmetric pattern foil. U researchers are developing new ways to harness infrared light with metal foils that could soon be integrated into faster and smaller communication technology as well as homeland security devices.