Question

To sustain lasing action in a three-level laser as shown in the figure, necessary condition(s) is(are) 

• A. lifetime of the energy level 1 should be greater than that of energy level 2
• B. population of the particles in level 1 should be greater than that of level 0
• C. lifetime of the energy level 2 should be greater than that of energy level 0
• D. population of the particles in level 2 should be greater than that of level 1

Hint:

In a three-level laser, to achieve population inversion and sustained lasing, the lifetime of the excited states and the population distributions must be carefully controlled.

Answer 1

The Correct Option is A, B

In a three-level laser system, to achieve sustained lasing action, certain conditions must be met to maintain the population inversion between the energy levels. 1. Condition (A): The lifetime of energy level 1 should be greater than that of energy level 2. This ensures that level 1 can accumulate more population before the system decays to level 0. If the lifetime of level 1 is too short, it will not effectively contribute to the population inversion needed for lasing. 2. Condition (B): The population of the particles in level 1 should be greater than that of level 0. For lasing to occur, there must be a population inversion, meaning that more particles should occupy the higher energy level (level 1) than the lower energy level (level 0). This condition is necessary for the laser to emit light. Thus, the necessary conditions for lasing are (A) and (B).