Condition on 4-potential to give left-circular polarized light?

To get a collection of left-circularly polarised photons, do we put a condition on the 4-potential $A_mu$?

Or is it a condition on the wavefunction $Psi[A]$ to say that the amplitude for right-circularly polarised photons is zero?

In other words, what is the condition for a field/collection of left-circularly polarised photons?

e.g. Given a solution to Maxwells equations and the 4-potential $A_mu$ what condition makes it left-circularly polarized? (Without explicitly giving a solution).

I feel like it would be some symmetry condition on $F_{munu}$