"Nature has simple ways of making structures and materials that are still unobtainable with our million-dollar instruments and engineering strategies," said Michael Bartl, an assistant professor of chemistry at the University of Utah. Bartl led a research team whose findings appear this week in Physical Review E, published by the American Physical Society.
Jeremy Galusha, one of Bartl's graduate students and a co-author on the study, learned of the beetle Lamprocyphus augustus after visiting a microscopy lab at Brigham Young University. There he met high schooler Lauren Richey who was leading a science project on iridescence in insects and was interested in the Brazilian beetle because its luminous color remained the same no matter the angle at which it's viewed.
"I saw the picture of it and I thought that must be a photonic crystal," she said. This property, known as "angle independence," suggested the physical structure of the beetle's scales was something unusual. Most iridescent objects, which achieve their color through their atomic structure rather than pigments, hold their shimmering color when viewed only from a certain position, said Galusha, a doctoral candidate in chemistry
He worked with Richey, now a BYU sophomore, to find complete specimens of the inch-long weevil, which they eventually obtained through an insect broker in Belgium. The researchers scraped off the specimens' scales, which are about as a wide as a human hair, and cut them into tiny cross sections.
Using an ion beam to shave down a scale, he produced 150 cross-section images, which he reassembled into a three-dimensional picture.
The team discovered the scale's crystal structure was much like that of a diamond, also known to possess photonic properties. Diamonds' composition, however, is too dense for use in computing. The beetle discovery is significant because the creature's scales could serve as a template from which to synthesize a photonic crystal that would enable the development of the next wave of computers.
"You would be able to solve certain problems that we are not able to solve now. For certain problems, an optical computer could do in seconds what regular computers need years for," said Bartl, also an adjunct professor of physics. "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."
Why did the beetle evolve angle-independent iridescence? It can't be camouflage, because the beetle's shimmer makes it stand out rather than blend into its surroundings. Bartl suggested it is designed to attract mates.
