TABLE OF CONTENTS Let us now address the laser effect. What does laser mean? Laser stands for Light Amplification by Stimulated Emission of Radiation.
A laser is a common, visible object: from blackboard pointers to disco lights, we recognize lasers because they have a perfectly defined color they are monochrome and because the beams are straight. Their rays diverge much less than a normal projector.
The qualities mentioned above are linked because we use the properties of a cavity [3] in order to amplify and monochromatize the light. This light is normally emitted spontaneously from certain materials by the fundamental process of luminescence.
We have seen that electrons in an atom occupy a clearly defined state of energy. In their basic state, they occupy the electronic state with the lowest energy. If we put an electron into a superior electronic state, it becomes excited. Very quickly it will become de-excited by emitting energy.
In an atom, the energy exchanges are carried out by photons. Excitation and de-excitation correspond to the absorption and emission of a photon respectively during energy exchanges between two different energy states. The emission is completed either spontaneously or by stimulation by the photons themselves following an entrainment process. There cannot be any amplification in this case since the more the atom becomes excited, the more it will become de-excited. At most, we have a balance between the atoms in their basic state and in their excited state.
Let...
