Akinbo,
You have an inability to realize that a *spinning* helical structure can be viewed as both a particle *and* a wave...Anyway, you've actually asked a good question here:
When your screws of light enter a glass block from air, they slow down from about 3x108m/s to 2x108m/s. When the screws emerge where cometh the energy to increase their speed on exit back to 3x108m/s?
I googled and found this answer from an optics professor:
Q: Yes, light is slower in material than air, and yes it is instantly speeds up again when it leaves the material. This is just like if you're running along a road (fast) then cut through a cornfield (slow) - as soon as you get out of the corn field, you can run at your original speed again.
A: As light passes through matter, the electric field field is constantly interacting with the electron cloud of the atoms. Because it is a wave, in some places, the electric field points up and in other places it points down. The electron cloud tends to want to move against this field (where the field points up, the electrons move downward, and vice-versa). The energy to move around this "dipole moment" comes from the electric field (note that this is distinctly different from the physical phenomenon of absorption and also different from reflection/scattering). As the wave passes by the dipole moment shifts the other direction, kicking that energy back out again. The dipole moment cannot shift instantly - this interaction essentially (I'm skipping alot here) results in the wave being coming out with a slight phase shift... making it seem that the light took longer to move the same distance (slowing down!).
The best analogy I have been able to come up with is to imagine that you're running a race through a series of revolving doors. Each time you hit a door, you slow down (transferring some momentum to the rotation of the door). As you pass through the exit of each door though, you get hit in the butt by the door, transferring the momentum back to you and returning to your original speed. Energy was never absorbed in this process (photon absorption results in the complete destruction of the photon) - a portion was just transferred to the door, and only for the duration of time that you were actually passing through the door.
Optics professor.
...........................................
Again, you ask a good question. The magnetic field lines of force go through opaque matter yet are supposed to be transmitted by photons. I googled and found this:
Light shining through walls
Shining light through walls? At first glance this sounds craz
y. However, very feeble gravitational and electroweak
effects allow for this exotic possibility. Unfortunately, w
ith present and near future technologies the opportunity to
observe light shining through walls via these effects is comp
letely out of question. Nevertheless there are quite a
number of experimental collaborations around the globe inv
olved in this quest. Why are they doing it? Are there
additional ways of sending photons through opaque matter? I
ndeed, various extensions of the standard model of
particle physics predict the existence of new particles cal
led WISPs - extremely weakly interacting slim particles.
Photons can convert into these hypothetical particles, whi
ch have no problems to penetrate very dense materials,
and these can reconvert into photons after their passage - as
if light was effectively traversing walls. We review this
exciting field of research, describing the most important WI
SPs, the present and future experiments, the indirect
hints from astrophysics and cosmology pointing to the exist
ence of WISPs, and finally outlining the consequences
that the discovery of WISPs would have.
.......................................
Alan
