THOMAS EBBESEN holds a piece of gold foil up to the light and looks through it. Made 14 years ago by technicians at the NEC Research Institute in Princeton, New Jersey - where Ebbesen was working at the time - at first glance the foil looks unremarkable. Peer at it under an electron microscope, though, and you would see that it is peppered with 100 million identical holes, each 200 times narrower than a human hair. But there's something much more extraordinary about the thin gold film: more light passes through the holes than strikes them.

It is a finding that challenges our entire understanding of light. According to optical theory, at 300 nanometres across the holes are so small they should only let through 0.01 per cent of the visible light that falls directly on them. But Ebbesen's experiment suggested they were transmitting more than 100 per cent. Somehow ...