Optics: Polarization rotation using polarizers | MIT Video Demonstrations in Lasers and Optics

Optics: Polarization rotation using polarizers
Instructor: Shaoul Ezekiel
View the complete course: ocw.mit.edu/RES...
License: Creative Commons BY-NC-SA
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[@golamnazib1298]

Thanks & دل سے شکریہ, شكرا جزيلا لك

[@thelowendstudio]

Just awesome

[@supersonic174]

I remember seeing a similar video, but stating that it was not understood how the light is able to come through in some cases.

[@uploadJ]

re: "but stating that it was not understood how the light is able to come through in some cases." Polarizers are not "filters", per se, but "re-radiators" of the EM or light waves (as the presenter in the video says, although subtly)... but, the polaizer must intercept some energy on their 'linear' segments, or elements, so the case of the 90 deg rotation then no energy is re-radiated since none was picked up, or intercepted, in the first place. That is to say, the 'elements' in a polarizer act like dipole antenna elements, with intercepted energy equal to the cosine of the angle, where cos(90) = 0.

[@swati2005bh]

really easy to understand and very well explained..Thanks for the video :) But I was wondering that how the use of 2 polarizers have enabled the rotation of light by 90 degrees? (basically I want to know the logic behind this phenomenon ...)

[@YodaWhat]

See this collaborative explanation by Minute Physics and 3Blue1Brown kzbin.info/www/bejne/sJTUi3uPpJyChNU

[@uploadJ]

Note, there is a PENALTY for this "rotation", the re-radiation of the RF, I mean light EM energy is at a cost of the cosine of the angle difference from polarizer to polarizer (neglecting a small amount lost in the polarizer regardless of angle). AS long as you can sustain this cosine loss, you can infinitely rotate the light.

[@uploadJ]

re: "(basically I want to know the logic behind this phenomenon ...)" Think: Re-radiation of the light at the angle of the last polarizer encountered. As long as the angle between the two is not 90 deg, then light, at the new angle, will be "radiated" by the polarizer or grating.

[@ebunny91]

@@uploadJ I thought that polarizers worked by blocking light that was not at the proper polarization to pass through. All of the light passing through one polarizer should then be parallel with each other. Isn't that correct?

[@uploadJ]

@@ebunny91 The light is at the angle of the **last** polarizer encountered ... nothing more, nothing less. IF the angle between two polarizers is 90 degs, then NO light makes its way through, according to the cosine of the angle, cos(90) = 0.

[@mahmoudabdelaal8468]

thank you :)

[@keithdutton1246]

תודה

[@cosmological7773]

Hmmm. 90° relative to what? If your "floating" in empty space what would make 90° 90°?

[@dalenassar9152]

I want to try and explain something in science class, but first, how do I get, with four polorizers, the MAXIMUM light change through the polorizers,for the MINIMUN rotation of any ONE polorid? Thank you so much, I spend all of my free time on it and, it is my last chance to make it to the science fair. And I want to thank my school for being kind and nice enough to let be take lab stuff home on weekends.

[@YodaWhat]

See this collaborative explanation by Minute Physics and 3Blue1Brown kzbin.info/www/bejne/sJTUi3uPpJyChNU

[@uploadJ]

@YodaWhat re: "See this collaborative explanation by Minute Physics and 3Blue1Brown" Sorry, that does not cut it. That is "obfuscation" by physicists because they THEMSELVES do not understand the simple phenomenon this actually represents.

[@uploadJ]

Better to understand THIS experiment first, before jetting off into Bell's theorem and QM nonsense - I give you the microwave experiment using a simple grate: kzbin.info/www/bejne/gX6VhZ6DZc2tjZo&t=116