Question

In a ruby laser, the stimulated emission is due to the transition from:

• A. Metastable state to any lower state
• B. Any higher state to lower state
• C. Metastable state to ground state
• D. Any higher state to ground state

Answer 1

The correct option is C

Metastable state to ground state

Explanation for correct option:

Option C: Metastable state to ground state

1. A laser in a solid state that uses a synthetic ruby crystal as its laser medium is known as a Ruby laser.
2. It contains small amounts of chromium that are responsible for the red color of the ruby laser.
3. The cycle consists of excitation, relaxation, and stimulated emissions.
4. There are transitions in three energy levels and therefore, a ruby laser is known as a three-level laser.
5. The stimulated emission is the transition of electrons from a metastable state to the ground state.

Explanation for incorrect option:

Options A, B, and D

In the stimulated emission, the transition is from a metastable state to ground state and not from any higher state to any lower state. Hence, it is incorrect.

Hence, Option (C) is correct.