Action of a lens in a dual-slit setup with different polarization filters ( and ) at the slits—slits 1 and 2 create a two-slit image and , denoted are the focal plane of the lens m, the image plane of the lens . Plotted are the probability density functions at the level of the optical axis () for photon with nm passing through square slits with side of 250 μm separated by distance of 2 mm. There is perfect which-way information due to entanglement of photon polarization with photon path, and there is no interference pattern at the focal plane of the lens.
