What's It Good For?

Left: A steel target used for a military laser experiment at the...

Fifty years after the first laser, there are few people in modern society who have not been affected by the invention.

Revolutionizing Communications. In the 1980’s telecommunication systems relied on bulky copper cable, which was at the limits of its signal-carrying capacity and had filled the duct space under city streets with no room for expansion. Laser light beamed through a single strand of glass optical fiber, thinner than a human hair, can carry more than half a million telephone conversations, or thousands of computer connections and TV channels. Without fiber optics the internet that brings you this exhibit would not exist.

The internal assembly for a Sony D-5 "Discman" CD player...

Improving Commerce, Industry and Entertainment. One of the earliest uses of lasers was in surveying. For example, to tunnel under the English Channel, separate tunnels were started from the English and French sides of the Channel. Laser surveying brought the two together with a misalignment of only a few inches over 15 miles. Today, supermarket checkout scanners, CDs, DVDs, laser holograms for security on credit cards, and laser printers are just a few of the countless consumer products that rely on lasers. Industrial lasers cut, drill and weld materials ranging from paper and cloth to diamonds and exotic alloys, far more efficiently and precisely than metal tools.

Spectra Physics model "A" Supermarket Scanner, one of the first ever used...

Pain free Surgery. Used in millions of medical procedures every year, lasers reduce the need for general anesthesia. The heat of the beam cauterizes tissue as it cuts, resulting in almost bloodless surgery and less infection. For example, detached retinas cause blindness in thousand of people each year. If caught early, a laser can "weld" the retina back in place before permanent damage results. Optical fibers can also deliver laser beams inside the body to reduce the need for more invasive surgery.

Advancing Science. Before any other application, lasers were used for scientific research. At first, like masers, they were used to study atomic physics and chemistry. But uses were soon found in many fields. For example, focused laser beams are used as "optical tweezers" to manipulate biological samples such as red blood cells and microorganisms. Five researchers have shared Nobel Prizes for using lasers to cool and trap atoms and to create a strange new state of matter (the Bose Einstein condensate) that probes the most fundamental physics. Over the long run, none of the uses of lasers is likely to be more important than their help in making new discoveries, with unforeseeable uses of their own.