Maser And Lasers

Maser is stands for Microwave Amplification by Stimulated emission of Radiation. A class of amplifiers and oscillators that make use of internal energy of atom and molecules to obtain low noise level amplification and micro wave oscillation of precisely determined frequencies. Stimulated emission, which is the basic principal n which these devices work, is emission the emission by an atom in an excited quantum state of photon, as the result of the impact of photon from outside of exactly equal energy. Thus stimulating photon, or wave, is augmented by the one emitted by the excited atom. A maser consists of an "active medium"in most of the atoms can optically pumped to an excited state by subjecting the system to electromegnatic radiation of different frequencies to that of stimulating frequency. An active medium is enclosed in a resonant cavity so that wave is build up with only one mode of oscillation, which is equivalent to a single output frequency. Maser can also be made to operate at optical frequencies, when referred to as optical maser or laser.

The term laser derived from the technical name for the process ; light Amplification by Stimulated Emission of Radiation.  Stimulation emission is the emission of a photon (a particle of light). Laser is an instrument  which produces a beam of light. However, laser light is much more powerful than ordinary light. It has such high energy that it can cut through very hard substances such as metal and diamond. metal are also joined together or welded , using laser.