  In this work we introduce a generalization of the Jauch and Rohrlich quantum
Stokes operators when the arrival direction from the source is unknown {\it a
priori}. We define the generalized Stokes operators as the Jordan-Schwinger map
of a triplet of harmonic oscillators with the Gell-Mann and Ne'eman SU(3)
symmetry group matrices. We show that the elements of the Jordan-Schwinger map
are the constants of motion of the three-dimensional isotropic harmonic
oscillator. Also, we show that generalized Stokes Operators together with the
Gell-Mann and Ne'eman matrices may be used to expand the polarization density
matrix. By taking the expectation value of the Stokes operators in a three-mode
coherent state of the electromagnetic field, we obtain the corresponding
generalized classical Stokes parameters. Finally, by means of the constants of
motion of the classical three-dimensional isotropic harmonic oscillator we
describe the geometric properties of the polarization ellipse
