Gene Fuller wrote:
I see we are back to the old business about colliding waves that
apparently carry vector power. At least it seems that way since the
counter-traveling power can cancel at some points and add up at other
points. I thought we trashed this idea a couple of years ago.

Please cease the obfuscation. It cannot be explained any
better than these two web pages. Please note that "intensity"
is a power density (watts/unit-area) and it is *energy* that
is redistributed, not voltage or current.

www.mellesgriot.com/products/optics/oc_2_1.htm

"Clearly, if the wavelength of the incident light and the
thickness of the film are such that a phase difference exists
between reflections of p, then reflected wavefronts interfere
destructively, and overall reflected intensity is a minimum.
If the two reflections are of equal amplitude, then this
amplitude (and hence intensity) minimum will be zero."
[Referring to 1/4 wavelength thin films.]

"In the absence of absorption or scatter, the principle of
conservation of energy indicates all 'lost' reflected intensity
will appear as enhanced intensity in the transmitted beam. The
sum of the reflected and transmitted beam intensities is always
equal to the incident intensity. This important fact has been
confirmed experimentally."

micro.magnet.fsu.edu/primer/java/scienceopticsu/interference/waveinteractions/index.html

"... when two waves of equal amplitude and wavelength that are
180-degrees ... out of phase with each other meet, they are not
actually annihilated, ... All of the photon energy present in
these waves must somehow be recovered or redistributed in a new
direction, according to the law of energy conservation ... Instead,
upon meeting, the photons are redistributed to regions that permit
constructive interference, so the effect should be considered as
a redistribution of light waves and photon energy rather than
the spontaneous construction or destruction of light."
--
73, Cecil http://www.w5dxp.com