A pure right-handed circularly polarized wave propagating along the
-axis takes the form
(5.56)
(5.57)
In terms of complex amplitudes, this becomes
(5.58)
Similarly, a left-handed circularly polarized wave is characterized by
(5.59)
The polarization of the transverse electric field is obtained from the
middle line of Equation (5.42):
(5.60)
For the case of parallel propagation, with , the previous formula
yields
. Similarly, for the case of parallel propagation,
with , we obtain
. Thus, it is clear that
the roots and in Equations (5.51)–(5.53) correspond to
right- and left-handed circularly polarized waves, respectively.