Curved patterns could find use in photonics, telecommunications
The green hairstreak butterfly (Callophrys rubi) gets its blue-green hue from complex nanoscale structures on its wings. The structures, called gyroids, are repeating patterns of spiral-shaped curls. Light waves bouncing off the patterned surface (top inset above) interfere with one another, amplifying green colors while washing out other shades (SN: 6/7/08, p. 26).
Scientists led by Min Gu of the Royal Melbourne Institute of Technology in Australia have now painstakingly re-created the gyroid structure by sculpting the shapes out of a special resin that solidifies when hit with laser light. The technique, called optical two-beam lithography, uses a pair of lasers to set the material in just the right pattern. Afterward, the remaining resin can be washed away, leaving only the gyroid structure. The fabricated version repeats its pattern every 360 nanometers, or billionths of a meter.