Interferenz zwischen senkrecht zueinander polarisierten Lichtstrahlen

From the quantum mechanical description of the photoelectric effect interference between two light beams polarized in orthogonal directions is predicted in case of a onephoton‐detector (with radial symmetric initial state of the electrons) if only photoelectrons propagating in a (properly chosen) solid angle are registered. If a two‐photon‐detector is used for observation interference between orthogonally polarized beams takes place also if all photoelectrons are counted, irrespective of their direction of propagation. In this case a beat signal at twice the difference frequency Δ v (but no signal at Δ v !) will occur.