Dowling and Gea-Benacloche (1992) proved mathematically that "...under certain circumstances, it is possible to
consistently interpret interference as the specular reflection of two electromagnetic waves off each other..." Combining
experiment, model, and logic, we confirm this statement. Contrary to the supposition that electromagnetic
waves/photons cannot interact, it is possible to interpret the results to indicate that identical out-of-phase waves and
opposite polarity photons repel or, at least, cannot pass through each other. No energy is detected in the dark/null zones
of wave interference. Because energy appears to be absent, the exchange of momentum through the null zone must
redirect/repel light waves into bright zones.
Our Zero-Slit Experiment (ZSX) provides diffraction-free interference in air between two portions of a divided laser
beam. This experiment was initially an attempt to completely cancel a section of these two beams by recombining them
in air when they are 180° out-of-phase. We have reduced interference patterns close to a double-bright zone (with 3 null
zones), but no further. Within the limits of laser-beam spreading, we have studied the resulting interference patterns and
compared them with models of collision between identical particles. It may be possible to distinguish light from other
Bosons, if the model of opposite phases repelling is valid.
An EM field-line model of the photon is presented to explain the interactions needed to produce momentum transfer.