The answer to the first question is that the orientation of the final polarizer determines the orientation of the light polarization of the film stack.

Allow me to review what happens, a first polarizer filters, cuts out light of the "wrong" polarization". But it doesn't just do this as notch filter would to frequencies... blocking all of the light photons with the "wrong" polarization"... no it blocks the light *components* with the wrong polarization.

Assuming that the orginal light was randomly polarized, there would be light components at all angles. Light can have both horizontal and vertical components... and can even have both of them in a phase relationship with one another such that they are twisting in time, and thus would be circularly polarized, with a handedness, right or left turning. Light can have unequal energy components... which we call eliptically polarized... and they can have all of the energ in one and not orthoganal orientation. We call that linear polarization. The linear polarizer would attentuate, block, all of the energy component of the wrong polarization, allowing all of the energy of the right polarization. This would mean that half of the energy go through.

When linearly polarized light then reaches another linear polarizer of in the othogonal orientation, all of the light *energy* of the "wrong" orientation is blocked. Since all of the light is the "wrong", none (or almost none, since no real polarizer is perfect) gets through.

Now, when a third polarizer, one oriented at 45 degrees from the first and last is introduced. The polarized light from the first has energy half of the energy in the right orientation and half in the wrong... so that half gets through... all of which is now in the new orientation. The final polarizer does the same thing, half is in the right orientation and half is in the wrong orientation, so the light is cut down by half again... making it only one fourth as much energy as came out of the first polarizer, or one eighth as much of the original non-polarized light.

From my explaination, you can answer the rest of the questions yourself. They don't make much sense... and no... there is no such thing as a "diagonal dimension" in the discussion of light polarization.

--Candice H. Brown Elliott