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    How a TFP (Thin Flim Polarizer) works?

    Hello. I've been really curious about how TFP (Thin Flim Polarizer) works. I've searched TFP information through the Internet which tells that TFP utilizes Brewster's angle. This explains how the P-polarization transmits TFP with 100 % transmission, but I don't know how the S-polarization is...
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    Closed loop problem for lighting in thunderstorm?

    Oh thanks. Yes. displacement current must be included to complete the circuit. Equivalent circuit that charged cloud and earth acts as a charged capacitor and lighting as a current through resistor is just beautiful. Can I have one more question? Once electrons are escaping from the cloud...
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    Closed loop problem for lighting in thunderstorm?

    Hello. As far as I know, every circuit capable to flow current must be closed. In other word, open circuit can not flow the current, obviously. Right now, I would like to know this is also true for lighting in bad weather. When bottom of the dark and heavy cloud get more and more electron by...
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    Light Polarization Reflected from Parabolic Mirror

    You can measure the beam profile in combination of objective lens (to magnify such a small spot to the size of many data-points). But as long as input beam is Gaussian and parabolic mirror is adjusted to get best focus, you can think Gaussian beam at the focus.
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    Light Polarization Reflected from Parabolic Mirror

    Okay. collimated beam at the focus is better seen via https://en.wikipedia.org/wiki/Gaussian_beam. Please see the 4th figure of Gaussian focusing. You can see that at the very exact point of focus, all k vectors of the beam becomes parallel with each other. That's th collimated I mean.
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    Light Polarization Reflected from Parabolic Mirror

    I'm not sure my geometric understanding of your setup is right. From my view of point, collimated beam height is higher than flat absorbing surface and parabolic mirror is positioned such that beam is focused-reflected to down to surface from the height. You might know that if the surface is...
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    Light Polarization Reflected from Parabolic Mirror

    You can have imagination of how polarization evolves when it is propagating. When the light, for example linear polarization, just traverses the space with preserving their direction, polarization is also maintained, of course. When they bend, vector along to polarization is also bent with the...
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