Science: Now, the Death Ray?

Like so many other triumphs of science, the laser has become a double-edged sword. Capable of producing an enormously powerful, very narrow beam of light, it has been used to perform delicate surgery on the retina of the eye, puncture tiny holes in material as hard as diamonds, produce three-dimensional pictures called holograms, and even measure the distance from earth to the moon (with an error of only a few inches). But the laser can also be used for less peaceful purposes. It provides, for example, the guiding light for the Air Force's...