First let's talk about lasers. A simple three level laser produces coherent light from stimulated emission, and incoherent light from unstimulated emission. I have been told that the intensity of light from the unstimulated emission is much lower because the light is incoherent and destructively interferes with itself to produce a low intensity compared to the light from the coherent transition which adds constructively.
My question is this: why does destructive interference between incoherent light rays like this not occur in light bulbs? Light bulbs produce incoherent light, shouldn't this light destructively interfere so that the lightbulb produces no (or very little) light?
