Can Geodesics on the Surface of Stationary Phase be Photon Trajectories?

A paragon to study the elementary wave theory in optics in addition to Young’s two slit experiment are two twisted slits [Frins; DGaO Proc.2019]. We determined the analytic representation of the geodesics as possible light trajectories on the surface of stationary phase of this arrangement and found them to be straight lines in real space. They cross the virtual slit witch was derived already from a simple graphic wave description of the two twisted slit model. These geodesics of light propagation through the slits are compared with a model of pure momentum conservation (witch explains scratch holograms [Frins; DGaO Proc.2013] and the glittering of spider nets in the sun); we find that agreement occurs only for a light source at infinity: Reasonable photon trajectories of an elementary phase theory in free space are straight and they are geodesics in the space of stationary phase but they can not be understood as to be purely momentum driven.