An interesting question popped into my head today regarding laser light. First, we know that all matter is made up of atoms, and that photons are considered to exhibit wave/particle duality. But if you shine a laser on a mirror, the light is reflected in a coherent way, i.e., the reflected laser beam remains concentrated and isn't spread out or noisy or diffuse. In other words, the angle of reflection equals the angle of incidence and it does not scatter.
The question is, why does it not scatter, given that a mirror is made up of atoms, photons should be hitting the atoms at different angles, and therefore scatter as they reflect from the mirror?
