  Exact Bateman-Hillion solutions of the wave equation are applied to
Hermite-Gaussian beams using a space-time constraint condition that requires
the field density to fall as the inverse square of distance from the focal
point of the beam at large distances from it. Following a familiar practice,
the constraint is implemented in integrals through the use of a Dirac delta
function. It is shown the Hermite-Gaussian functions evolve to become pure
functions of angular position on the fully developed spherical phase fronts.
Under the paraxial approximation it is further shown the wave equation and
Schrodinger equation are interchangeable within the constraint space in
correspondence to a recent paper claiming indirect evidence of Gouy phase in
matter waves.
