Diamond delight
Imagine a gear only three hairs wide. Difficult? Not for Paul Christensen, president of Potomac Photonics Inc of Maryland, USA, who carved a miniscule gear into a flat diamond surface using a laser (Science, Vol 261, No 5129). The gear is about 300 microns (three hair-widths) across with a dozen teeth 50 microns wide.
Such micro-parts could have fascinating possibilities, from innards of gnat-sized robots to tiny cutters that slice beams of light into information-carrying bits. However, Christensen is still trying to dig the gear out of the diamond and hopes to solve the problem by creating a gear cut-out from a thin sheet of synthetic diamond.