The size and shape of a single photon is a property of photon shown in the collision of the photon with charged particles. Applying scattering theory and classical electrodynamics is the most reliable way to solve this problem. The main intention of this paper is to reveal the electromagnetic structure of a single photon. It establishes the formulas for the Poynting vector (energy flow vector) and the energy density. Applying the new explanation of Compton wavelength creates the probability formula for the Compton effect when a photon collides with an electron. The research discovers that the electromagnetic field of a single linearly polarized photon confines to a membrane-like cuboid, while the electromagnetic field of a single circularly polarized photon confines to a membrane-like shell of a hollow cylinder.
Zu, D.L. (2008) The Classical Structure Model of Single Photon and Classical Point of View with regard to Wave-Particle Duality of Photon. Progress in Electromagnetics Research Letters, 1, 109-118. https://doi.org/10.2528/PIERL07111101