The name LASER is an acronym for Light Amplification by the Stimulated Emission of Radiation.
Light is really an electromagnetic wave. Each wave has brightness and color, and vibrates at a certain angle, so-called polarization. This is also true for laser light but it is more parallel than any other light source. Every part of the beam has (almost) the exact same direction and the beam will therefore diverge very little. With a good laser an object at a distance of 1 km (0.6 mile) can be illuminated with a dot about 60 mm (2.3 inches) in radius. As it is so parallel it can also be focused to very small diameters where the concentration of light energy becomes so great that you can cut, drill or turn with the beam. It also makes it possible to illuminate and examine very tiny details. It is this property that is used in surgical appliances and in CD players. It can also be made very monochromic, so that just one light wavelength is present. This is not the case with ordinary light sources. White light contains all the colors in the
spectrum, but even a colored light, such as a red LED (light emitting diode) contains a continuous interval of red wavelengths. On the other hand, laser emissions are not usually very strong when it comes to energy content. A very powerful laser of the kind that is used in a laser show does not give off more light than an ordinary streetlight; the difference is in how parallel it is.

Autore
Jagdeep Singh