Question

Explain why laser action cannot occur without population inversion between atomic levels

Answer 1

Answer:

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Answer 2

Answer:

Laser action cannot occur without population inversion between atomic levels because it is the necessary condition of stimulated emission.

Explanation:

Population inversion- It is the process of achieving a larger number of atoms in the higher energy level than the lower energy level.

• The laser action occurs only when there is a stimulated emission of light.

• In stimulated emission, an electron in an excited state can make a transition to a lower state under the influence of an incident photon of frequency "ν".As a consequence, two photons move together.
• This stimulated emission is only possible when the number of electrons is more in the excited state than in the lower energy state. Hence, population inversion has to take place for laser action to occur.