Doesn’t the same thing happen with laser light?
Question: From the point of view of classical optics, the experimental result is not particularly surprising. It is well known that interference only occurs when beams of light with the same direction of polarization are superimposed. So why is the experimental result remarkable at all?
Answer: It is indeed true that classical optics correctly predicts all results of experiments with “macroscopic” light. From the point of view of classical optics, there is nothing mysterious about the disappearance of the interference pattern when the polarization filters are set orthogonally to one another. The experimental result only becomes astonishing when one considers experiments with individual photons. Only then can the experiments be interpreted in such a way that they shed light on the peculiar behavior of quantum objects (as will be explained further in the course of this lesson).