I remember a post where the radius of a photon was calculated but was too big, around a few millimeters. Then I was reminded of Newton's double prisms experiment where a second prism, inverted, was placed in the path of a ray through a first prism, not touching but a few millimeter apart. The ray recombined in the second prism in spite of the spacing. Tunneling was the conventional explanation. It might suggests that photons have a wider radius.
Then there is the double slit experiment where light spreads beyond two parallel narrow slits.
What about this?
where the reflective index of the transparent material is varied?
In the case of a single slit, is it possible to steer the photons by varying the reflective index (as in a piezo-electric material) as they pass through the slit.
Good night.
