Brazillian beetle

Researchers studying ways to use light waves instead of electricity to drive ultra-fast computers have discovered an unlikely development tool: the iridescent green scales on inch-long beetles found in Brazil.

Microscopic crystals, not pigment, give the Lamprocyphus augustus beetle a brilliant color and sheen. The crystals have a diamond-like structure that gives them "photonic crystal" properties scientists have not been able to create in the laboratory.

The discovery is the focus of a study by University of Utah assistant professor of chemistry and adjunct assistant professor of physics Michael Bartl and chemistry doctoral student Jeremy Galusha. Co-authors are Brigham Young University student Lauren Richey, BYU biology professor John Gardner and Jennifer Cha, of IBM's Almaden Research Center in San Jose, Calif. The study is scheduled for publication this week in the journal Physical Review E.

Galusha was using an electron microscope at BYU where Gardner's group was helping Richey, then a Springville High School student, with a science fair project on iridescence in biology. Galusha first learned of the beetle project there and determined the 3-D structure of the scales using the scanning electron microscope.

Richey's first beetle specimen cost about $10, plus shipping, from a dealer in Belgium, Bartl said.

"It appears that a simple creature like a beetle provides us with one of the technologically most sought-after structures for the next generation of computing," Bartl said. "Nature has simple ways of making structures and materials that are still unobtainable with our million-dollar instruments and engineering strategies."

Bartl said the sparkling colors of an opal have a similar iridescent effect but a simpler

structure that does not aid research in technical applications. Beetle scales are too soft to be used in prototype or production computer parts, and they lack essential semiconductor properties. But the crystals do allow scientists, for the first time, to work with material that has the ideal structure for a photonic crystal.

"Nature uses very simple strategies to design structures to manipulate light — structures that are beyond the reach of our current abilities," Galusha said.

Bartl and Galusha now are trying to design a synthetic version of the beetle's crystals, using scale material as a mold. Commercial results are years away but very promising. "You would be able to solve certain problems that we are not able to solve now," Bartl said. "For certain problems, an optical computer could do in seconds what regular computers need years for."

According to the U., researchers also are seeking ideal photonic crystals to amplify light to make solar cells more efficient, to capture light that would catalyze chemical reactions and to generate tiny laser beams that would serve as light sources on optical chips.

"Photonic crystals are a new type of optical materials that manipulate light in non-classic ways," Bartl said. Some colors of light can pass through a photonic crystal at various speeds, while other wavelengths are reflected as the crystal acts like a mirror.

Bartl said there are many proposals for how light could be manipulated and controlled in new ways by photonic crystals. "However, we still lack the proper materials that would allow us to create ideal photonic crystals to manipulate visible light. A material like this doesn't exist artificially or synthetically."

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