As we have discussed in the previously, that principle of laser is stimulated emission and for it to take place, population inversion has to be
When energy is given to laser medium (solid, liquid or gas), then only a small fraction of laser medium shows lasing action. This part of
Three main components of laser device are: a) Active medium: For example in ruby laser, the active medium is aluminum oxide doped with .05 percent
The lasers can be classified on the basis of state as explained below: a) State of laser medium: According to the state of laser medium,
It is also the excited state but having life time of 10-5 to 10-3 seconds. Population inversion occurs only in between the metastable state and
Normally the population density of atoms/electrons is more in the ground state than the excited state. But if the process of stimulated emission dominates over
If the atom is in the excited state E2 and a photon of energy exactly equal to E2 – E1 = hυ is incident on
If the atom in the excited state automatically decays to the ground state by emitting a photon of energy (E2 – E1 = hυ), then
Stimulated Absorption is the starting point to achieve laser. It happens when a photon of light having energy E2 – E1 = hυ (as shown
A laser beam has the following important characteristics: 1. Directionality: An ordinary source of light emits light waves in all the directions and is highly
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