What is Prokhorov's theory of stimulated emission?
Stimulated emission is not a miracle; it is a consequence of quantum statistics. In a system of atoms with a population inversion—where more atoms are in an excited state than in the ground state—an incoming photon of the right frequency can trigger the emission of a second identical photon, coherent in phase and direction. This is the core of maser and laser action. My work with Basov focused on achieving this inversion in molecular beams and later in solid-state crystals. We showed that a resonator, such as a Fabry-Perot cavity, is necessary to sustain oscillation by providing feedback. The key is to overcome losses with gain. I detailed this in my 1958 paper 'Molecular Oscillators and Amplifiers,' where we derived the conditions for self-sustained oscillations. Without population inversion, there is no amplification—only absorption.
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