It is argued that the photon tunneling process originates in an inability to localize photons completely in space. Seen in this perspective, optical tunneling experiments might allow one to obtain rich information on the photon localizability problem, that until now has been studied mainly theoretically. A rigorous analysis of the electrodynamics in the near-field zone of matter enables us to identify the transverse vector field and subsequently to use it to construct a first-quantized space–time theory for the photon birth process and to determine the source region of the photon. The present theory shows that optical tunneling never appears outside the photon’s source domain, and it is shown that an apparently superluminal response occurs as a consequence of the lack of complete photon localizability. No fundamental velocity is attached to this effect, which stems solely from quantum nonlocality. Starting from the Riemann–Silberstein vectors, which permit the introduction of a space–time description of a free polychromatic photon’s so-called energy wave function, a theoretical investigation of the near-field scattering of a single photon from a mesoscopic or microscopic (molecular, atomic) particle is presented. Inasmuch as the photon tunneling phenomenon appears to be an indispensable part of the near-field scattering process, it might be possible to establish a rigorous first-quantized theory of one-photon tunneling between macroscopic molecular solids by adding the tunneling contributions from the individual molecules.
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