Ludwig wrote:
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. . .
I have a problem with solids and liquids. Let me introduce it in a very
simple conext. Light travels through a fiber cable whose diameter does
not exceed one wavelength. (A technical term "monomode" is often used to
describe this kind of an optical wave guide). The cable is one meter long.
Suppose it is made from pure SiO2. The size of each molecule (3 nuclei
and 44 electrons) is about 3*10^-10 meters and molecules are closely
packed. We can thus say that the cable is composed of 3*10^9
"monomolecular layers".
At the speed od 2*10^8 m/s the time to pass through the cable is 5 ns,
or 2*10^-18 seconds per layer. Is this enough to abrsorb and reemit
a wave? Keep in mind that the wave frequency is of the order of
5*10^14 Hz (T=2*10^-15 s). How can a wave be absorbed and reemitted
during 1/1000 of its period?
Ludwik Kowalski
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Ludwig,
Does this problem go away if you consider the steady state
situation, rather than the transient situation? Remember the resultant wave
in the second medium is the superposition of the original incident wave
and the waves generated by the induced oscillations of the medium molecules;
each of these constituent waves travels at the vacuum velocity c.
Also consider: the original incident wave existed "almost everywhere",
before you introduced the second medium (depending on just what was your
procedure).
(Of interest here is the extinction theorem of Omnes, et al [1915]).