Mechanics of a Laser
The two primary components of the laser are the active laser medium and the resonant cavity. The medium is a focused material that amplifies the beam through a process called stimulated emission. In this process, matter is agitated by a photon. At this point, the matter loses energy, and another photon is created. The original photon, however, remains intact, and shares practically the same phase and frequency as the resultant photon. Through this process, nearly identical particles are created, which results in the creation of laser light.
The laser light passes through the resonant optical cavity, which contains reflective surfaces that amplify the intensity of the light. The amplified light is outputted and a laser beam is formed.
Uses of Lasers
Because of the purity of the light source and the consistency of the wavelength, lasers are useful in many everyday applications. The barcode scanner, used in many retail applications, was invented in 1974. The musical compact disc player was invented in 1982. Lasers are also used in telecommunications to transmit information through the use of fiber optic technology. The medical disciplines also make judicious use of the laser; laser scalpels are utilized for vision correction and other surgical procedures. Dermatologists use lasers to remove tattoos, hair, and other growths on the surface of the skin.
Laser Beams
Despite their portrayal by Hollywood, laser beams cannot be seen in the vacuum in space. In the presence of air, a laser beam is made visible by its contact with particles such as dust. However, without air, a laser beam is invisible. Also, laser beams travel at the speed of light; their travel through space is unlike that of other conventional projectile weapons such as bullets or missiles. The emission of lasers also does not involve a “zap” sound; the only sound associated with laser emission is the sound of the equipment used in their production, which is usually described as a low-pitched hum.
