Hello, the resonator of a laser system is said to have 3 functions: Amplification in one direction, selection of one or few frequencies, and enhancement of coherence. I have a question about the coherence part. I see that the stimulated emission process produces phase matched light. Initially a spontaneous emission generates a weak standing wave with a certain phase inside the resonator. Then the stimulated emission contributes to that standing wave by adding photons of same phase. Thus, that particular standing wave can grow further. But the resonator also allows for the coexistence of other standing waves with different phases, right? I mean this is simply superposition. A moment later, another spontaneous emission occurs, sowing the seed for another standing wave, with a somewhat different phase. This one is again amplified by stimulated emission. The laser can therefore emit a superposition of light components, whereby each of the components is coherent taken by itself, but the superposition is not, because of the fact, that the laser cultivates standing waves of random phase relation due to initial spontaneous emissions. Where is the catch?