Polarization is the property of a transverse wave that describes its vibration direction, so that light can polarize confirms it is a wave. If quantum spin actually occurs, as proposed here, it will have a rotation axis around which the spin occurs. If a photon spins around its movement axis as a bullet does (Figure 3.19), its vibration is turning around that axis, but why then doesn’t the spin of a photon alter its polarization?
To understand this, consider a book sitting on its edge on a table. If the book spins within the plane of the table, its height direction doesn’t change because it is at right angles to table. Hence, if the table surface is our space, a photon spinning in our space doesn’t change the transverse vibration direction that defines its polarization (Note 1).
However when a filter that blocks horizontally polarized light is turned, it lets through more and more light until eventually it all gets through. Why then does turning a filter reduce the polarized light it blocks but turning a photon doesn’t affect its polarization? In the table analogy, the book height represented the vibration amplitude of a photon moving across the table surface. Spinning the book didn’t alter its height, but a filter is like a thin wall that blocks a wave moving on the table when it is face-on. But as that wall is turned, it obstructs the wave less, until at right angles it lets it all through (Note 2).
Why then do some photons pass entirely through a filter on an angle? Again, it is because a physical event is an all-or-nothing affair. The filter reduces the probability that instances get through but if one is detected, the entire photon restarts there. By the same logic, what passes through the filter is also an entire photon. The photon travels like a wave because it is a wave, but is detected like a particle because processing always restarts completely.
Note 1. Let the photon’s wave amplitude be in a direction Q, at right angles to its polarization plane XY. Now if the photon spins in the plane YZ, this swaps its Y and Z values but leaves Q unchanged, as it is at right angles to that spin. It follows that a photon can spin around its movement axis X without altering its amplitude vibration, and hence its polarization plane.
Note 2. If Q is the quantum amplitude it reduces as Q.Cos(q°), where q° is the angle between that amplitude and the filter direction in quantum space, so at a 90° angle it has no value, as Cos (90°) = 0.