Definition of LASER
Popularly known as Light Amplification by Stimulated Emission of Radiation is one of the important discoveries of the twentieth century. Its output is a narrow intense beam of light. It was firstly developed by T. Maiman in USA.
Principles of LASER
There are many Principles of LASER action. Mainly three types of transitions can occur between two energy levels in an atom, involving electromagnetic radiations.
So the three principles to produce LASER are-
¤ LASER production by Absorption process
¤ LASER production by Spontaneous Emission
¤ LASER production by Stimulated Emission.
Einstein gave very important relations/co-efficients which are very helpful to determine the characteristic of a LASER.
More articles: LASER Principals