Question

Q.40 A system in which population inversion is achieved is known as​

Answer 1

Population inversion can be achieved by optical pumping in which the atoms in the ground state are excited to higher states by absorption of pump light. ... The second type involving pump, upper, lower and ground levels is known as a four-level laser system.Population inversion is a process of achieving more electrons in the higher energy state than the lower energy state. In order to achieve population inversion, we need to supply energy to the laser medium. The process of supplying energy to the laser medium is called pumping.

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Answer 2

Answer:

A system in which population inversion is achieved is known as​ optical pumping

Explanation:

• Usually, the number of atoms in the lower energy state is more than the number of atoms in the excited state. To emit photons that are coherent, the number of atoms in the highest state must be greater than the number of atoms in the lower energy state. In other words, the population of atoms in the higher energy state must be larger than the population of atoms in the higher energy state must be larger than the population of atoms in the lower energy state. The process of making the population of atoms in the higher energy state more than that of the lower energy state is known as population inversion.
• The method by which population inversion is obtained is called optical pumping.