I got the explanation about stimulated emission and lasers as explained here: Understanding Stimulated Emission: Got the what, how about the why? What I'm still unsure about is if this also explains the simpler question of how light passes through a transparent medium, like glass, yet the photons still retain their original momentum vector from the source, so an image can be reconstructed spatially. In this case we are not talking about coherent photons, like in a laser. However, that shouldn't matter in terms of a high flux of photons passing through a material. I imagine an atoms-eye view, with a stream of photons all the same frequency (color) coming from a pinpoint on the source at me. There are so many that there's never any opportunity for spontaneous emission, thereby losing the direction information from an absorbed photon. Rather, I imagine photons being absorbed and then immediately readmitted via stimulated emission because there is a flood of other photons hitting the cross section of the atom. IF this concept is correct, there is an interesting side-effect: When the light gets dim enough, so that the flux is on the order of photons separated by more time than most spontaneous emissions, the material effectively becomes opaque, the photons are scattered rather than retaining their momentum vector. Keep in mind we exist in a transparent medium -- air -- that photons are passing through. So -- experts, how does this look?