squared

Although the squared magnitudes of scalar wave functions are commonly identified with the irradiance of the field, the data plotted in Figs.

These irradiances are given by the squared magnitudes of the basic Sommerfeld functions [u.sub.s] and [u.sub.s] themselves, and thus the quantities [\[u.sub.s] - [u.sub.s]\.sup.2] or [\[u.sub.s] + [u.sub.s]\.sup.2] do not represent the irradiances of the field for p- and s-polarized light.

According to the principle of interference, the observable Poynting vector is given by the incoherent vector sum of its components in the forward and reverse components, and thus it is impermissible to express the near-zone irradiance of the field as the squared magnitudes of scalar wave functions.

where m = (0,1,0) is the unit vector in the direction of the positive y-axis, [epsilon] and [micro] are the dielectric constant and magnetic permeability of the medium of propagation, and normalization factors were used so that the squared field vectors have the dimension of irradiance [W/[m.sup.2]].