2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/174083In this paper, applying the spinor representation of the electromagnetic field, we present a quantum-mechanical description of waveguides. As an example of application, a potential qubit generated via photon tunneling is discussed.13 pages, no figure, to be published in Chinese PhysicsClassical PhysicsGeneral Physicstext