18 September 2009
Vol 325, Issue 5947
About the Cover
Scheme of a photonic metamaterial composed of three-dimensional gold helices, each about 1.4 micrometers in diameter, fading to an oblique-view electron micrograph of the helices as fabricated (blue). The illuminated spiral symbolizes circularly polarized light impinging on the chiral metamaterial. The structure works as a circular polarizer for a frequency range exceeding one octave. See page 1513).
Illustration: Michael S. Rill (structure fabrication by Justyna K. Gansel and Michael Thiel)