What's the connection between the spin of the photon and the polarisation of light? In view of wave-particle duality, the spin of the photon must have a counterpart in the wave picture: is this polarisation?
 A: The photon as an elementary particle   is  special: the quantum mechanical wave equation whose solutions squared will describe the probability of finding the photon at a given phase space point is the Maxwell equation that describes the classical electromagnetic wave, except  it is the potential form of it and it acts as an operator on the wave function of the photon.
In a convoluted way, photons in huge numbers build up an electromagnetic wave, as shown here. An individual photon has energy equal to h*nu, and spin either parallel or antiparallel to its direction of motion. In building up the classical wave the phases describing the wave function of the photon will build up the polarization seen in macroscopic classical electromagnetic waves , i.e the changing electric and magnetic fields that describe the classical wave.
This experiment shows a direct link between the polarization of a laser beam and the spin of photoelectrons, the laser beam polarization is classical and the interaction with the electrons quantum mechanical, so yes there is the connection of continuity between classical and quantum descriptions.
A: Each photon has an oscillating electric and a magnetic component. In vacuum the components are always perpendicular to each other and also perpendicular to the motion of the photon (see this sketch). When photons are unpolarized, these oscillations are equally distributed in 360 °. A polarization grid can rotate about 50% of the photons so that they can pass through the grid. These photons are polarized now.
But the photons also have spin -1 or +1 yet. This is because the electric and magnetic components have a +/- or north-south orientation. The second orientation see this sketch.
