Zapping with the light fantastic

Lasers that pulsate at fantastically fast speeds have applications in engineering, computing and medicine
Mar 27th 2008
From The Economist print edition

EVEN the blink of an eye is nowhere near fast enough. To get an idea of how quickly the latest ultra-fast lasers operate, try an F-16 fighter. With the throttles fully open at supersonic speed the jet would barely traverse an atom in the same time as a pulse from one of today's fastest lasers.

Instead of emitting a continuous beam, a pulsed laser concentrates its energy into brief bursts. An ultra-fast laser produces fantastically short bursts in which the intensity and power of the pulses can reach mind-boggling levels. Because the pulses happen so quickly, the effects are concentrated in time. This gives ultra-fast lasers valuable properties that their slower predecessors do not have. They can, for instance, cut something out before the energy from the pulse gets a chance to heat up and possibly damage the surrounding area. This means ultra-fast lasers are better at such jobs as cutting and welding, eye surgery and creating some of the smallest man-made structures on the surface of semiconductors. the rest image