Laser

The term laser is an acronym for "light amplification by stimulated emission of radiation".

Lasers have the following properties:

• outstanding monochromaticity (the beam consists of a purely single wavelength);
• Outstanding directivity (the beam consists of parallel light waves that do not diffuse when propagating);
• High coherence (all the light waves of the beam are the same with each other).

The difference between an ordinary light and a laser beam

Lasers emit beams of light with high directionality, i.e., the light waves that are composed of light travel in a straight line and do not diffuse. The light waves emitted by ordinary light sources diffuse in all directions. The light waves within the laser beam are all of the same color (this property is called monochromacy). Ordinary light, such as that emitted by fluorescent tubes, is generally a mixture of several colors of light that appears white. When light waves within a laser beam propagate, they oscillate in perfectly synchronized peaks and troughs, a property known as coherence. When two laser beams overlap each other, the peaks and troughs of each beam only reinforce each other, producing an interferogram.