Fastest molecules for optical technologies
EVER SINCE optical technologies became prominent in the 1970s, researchers have tried to improve the materials used to handle light.
New materials, organic molecules known as chromophores, interact more strongly with light than any molecules ever tested.
Prime candidates
That makes them, or other molecules designed along the same principles, prime candidates for use in optical technologies such as optical switches, Internet connections, optical memory systems and holograms.
The Internet could soon shift into overdrive thanks to this new generation of optical molecules developed and tested by a team of researchers from Washington State University, the University of Leuven in Belgium and the Chinese Academy of Science in China.
Theoretical calculation
The molecules were synthesized by chemists in China, evaluated according to theoretical calculations by a physicist at WSU and tested for their actual optical properties by chemists in Belgium, according to a Washington State University press release.
"To our great excitement, the molecules performed better than any other molecules ever measured," said WSU physicist Mark Kuzyk. The team's findings are published in journal Optics Letters, available online.
In 1999, Kuzyk discovered a fundamental limit to how strongly light can interact with matter. He went on to show that all molecules examined at that time fell far short of the limit.
Even the best molecules had 30 times less "optical brawn," as he calls it, than was theoretically possible.
The molecules described in the new report break through this long-standing ceiling and are intrinsically 50 per cent better than any previously tested, which means they are far more efficient at converting light energy to a useable form.
Other researchers in the field hailed the breakthrough.
In the new designs, each molecule has a component at one end that donates an electron and a component at the other end that accepts an electron. In between is the `bridge' portion of the molecule. Previous efforts to boost the interaction with light focused on `smoothing out' the bridge to allow electrons to flow more easily from donor to acceptor end.
Kuzyk's calculations showed that a more `bumpy' structure actually enhanced the interaction with light; and Koen Clays, chemist at the University of Leuven, recognised that Zhao Yuxia (chemist at the Chinese Academy of Sciences)'s structures filled the bill — which was confirmed by measurements made by his group. Quantum mechanics explains the behaviour of electrons in this situation, Kuzyk said.
Speed bumps
"When you're looking at something like an electron, you can't really think of it as a classical little ball that's moving around," Kuzyk said. "In reality what ends up happening is that the electron is in a lot of places at the same time. When the electron is all spread out, it can be interfering with itself. By inserting these speed bumps, you're causing it to bunch up in certain places, and preventing it from interfering with itself." The molecules described in the current report have just one `speed bump.' — Our Bureau
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