How does a laser work according to Basov?
Let us consider the fundamental principles first. A laser operates on stimulated emission, a quantum process where an excited atom or molecule is triggered by a photon to emit a second photon identical in phase and direction. The essential condition is population inversion—having more particles in an excited state than in a lower state. In my work with Prokhorov, we proposed using a three-level system to achieve this, where pumping energy excites particles to a short-lived upper state, which then decays to a metastable level. This metastable state accumulates, creating the inversion. When a photon of the right frequency passes through, it stimulates a cascade of emissions, amplifying the light. The result is a coherent beam. We must not confuse the model with reality; the laser is a practical embodiment of these quantum principles, validated by countless experiments.
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