Their unique properties make lasers valuable tools with a large variety of applications.

Laser beams are used for obtaining accurate alignment of parts in engineering projects such as the construction of buildings and the laying of pipelines. Precise measurement of long distances can be made by determining the time it takes for a pulse of light from a laser to travel to a distant object and return. Using this method, scientists have measured precisely the distance between the earth and the moon by directing laser beams from earth onto reflectors left on the moon by Apollo astronauts.

The intense light of powerful lasers can cut through or heat many materials more quickly and easily than can conventional tools. In industry, laser beams are used for a variety of manufacturing operations, from cutting textiles to drilling holes through hard metals. A laser can produce intense heating over a small area, making it ideal for certain types of welding.

Lasers are used for delicate operations on the eye, brain, and other organs where conventional operating methods are often difficult. In surgery to repair detached retinas, for example, the laser beam can be passed through the lens of the eye and, in effect, weld breaks in the retina; the lens and other transparent parts of the eye are unaffected by the beam. When lasers are used as surgical knives, the heat from the laser beam immediately seals off severed blood vessels in the tissue being cut, thus minimizing bleeding.

Tiny lasers that can be turned on and off millions of times a second are used to transmit telephone messages and other information as flashes of light through optical fibers. Lasers are also used in certain electronic devices to read specially encoded information. For example, some supermarket optical scanners use a laser to read the Universal Product Code on grocery items at the checkout counter, and compact disc players use a laser to read data recorded on a small plastic disc.

Laser-guided missiles have proven highly accurate; the target is illuminated by the laser beam and the missile's guidance system uses the beam's reflection to home in on the target. Experimental lasers that can disable missiles at a distance in the air have been successfully tested.

Lasers are used by chemists to analyze the composition of chemical substances and to study chemical reactions. In the field of nuclear energy, some scientists think very powerful lasers are the key to making a successful fusion reactor. The lasers would provide the tremendous heat needed to start the fusion process.

Another important application of lasers is in holography, a method of producing three-dimensional images.