  We propose, as another pedagogical approach, a quantification of the e.m.
field better adapted in isolated systems, a quantification of e.m. fields in
finite-spacetime which does not rely explicitly on the notion of photon, nor on
the general application of gauge. Being based on the development of e.m. field
in TE-TM modes and states, it obeys the limit conditions of a finite-spacetime
which follows from the solution of an eigenvalue equation and allows to
interpret more profoundly some phenomenons, notably: the equivalence of a Pauli
principle in stationary TE-TM states, the notion of non-locality in a radiation
field, a modified form of the De Broglie analysis and the notion of
wave-paquets in finite-spacetime.
