  A non-perturbative quantization of a paraxial electromagnetic field is
achieved via a generalized dispersion relation imposed on the longitudinal and
the transverse components of the photon wave vector. The theoretical formalism
yields a seamless transition between the paraxial- and the Maxwell-equation
solutions. This obviates the need to introduce either "ad hoc" or
perturbatively-defined field operators. In the limit of narrow beam-like
fields, the theory is in agreement with approximated quantization schemes
provided by other authors.
