Question

To achieve optical amplifications, it is essential to create a non-equilibrium distribution of atoms.

(a) True

(b) False

This question was addressed to me in a national level competition.

This interesting question is from Population Inversion in chapter Laser of Engineering Physics II

Answer 1

Right answer is (a) True

The explanation is: We know, N2/N1 = e\(\frac{-hv}{kT}\). Thus, in normal situation, N1 > N2 for E1 < E2. Thus, to achieve lasing action, non-equilibrium distribution of atoms in such a way that the population of the upper energy is greater than that of the lower energy level.