What is the main operating principle of a laser device?
Answer and explanation
Correct answer: A. Stimulated emission of radiation with population inversion
- Step 1: Laser stands for Light Amplification by Stimulated Emission of Radiation.
- Step 2: It requires an active medium with population inversion (more atoms in a metastable excited state than the ground state) and stimulated emission triggered by resonant photons inside an optical resonator.
Answer
Stimulated emission of radiation with population inversion.
Why not the others: 'Spontaneous decay of thermal nucleons' produces incoherent gamma radiation; 'Direct photoelectric electron absorption' absorbs photons rather than amplifying them; 'Electrostatic charge accumulation' describes capacitor charging.
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