Circularly Polarized Light Explained

/ edmundsj
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How can light travel in a circle? In this video, we explore circular polarization, where the electric and magnetic fields of a plane wave trace out a circle in space. We also go over the Jones vectors for right-hand circularly polarized and left-hand circularly polarized light, and hopefully clear up some of the confusion around the conventions used.
This is part of my graduate series on optoelectronics / photonics, and is based primarily on Coldren's book on Lasers as well as graduate-level coursework I have taken in the EECS department at UC Berkeley.
Hope you found this video helpful, please post in the comments below anything I can do to improve future videos, or suggestions you have for future videos.

[@chromax1619]

ahahah i laughed so hard 5:23 that you were tryna say wtf politely

[@myothersoul1953]

That's the only part of the video I understood

[@Serdy]

Phenomenal. I'm so glad he didn't edit this part out.

[@user-fh8vl2xg7u]

5:20 Only this remained in my brain for the whole day 😂😂😂

[@Ana12956]

Please make more videos . Very clear concise and useful information

[@meetoptics]

Agreed! The photonics community needs this kind of content

[@apoorvsom9120]

Awesome explaination Jordan! Thank you very much. It helped me a lot for my physics exam

[@SciencewithSteph]

Thanks for this! I was looking for a succinct way to explain circularly polarised light and I ended up linking this video in mine to supplement my explanation of polarised light!

[@meetoptics]

Yeah, thank you so much for the explanation!

[@shiroma8007]

Very, very nice explanation. Thanks for being so clear and nice. About the elliptical polarised light, I could not find it. If you still have this video I will be glad watching this too.

[@meetoptics]

It is so good! Completely agreed

[@wolfy5825]

It's clear, short, efficient. Thank you very much !

[@sumantchopde9039]

Thanks a lot! I've an exam tomorrow and you cleared all my doubts! Very clear explanation!

[@meetoptics]

That's so great! Congratulations

[@meetoptics]

Congratulations for being able of introducing this technology to society through these videos. This platform let us spread all we know about the field and from MEETOPTICS we are proud to be part of the photonics community and to help engineers and researchers in their search for optical lenses through our site. We celebrate every step forward.

[@caden7745]

Thanks man, appreciate it!!!

[@deepinmoutain]

this is the best explanation! thank you!

[@subliminalvibes]

Please can you explain why my polarised filter is able to block light in one direction and not in the other direction?

[@ninakanska7124]

Gosh I love you. You explained it so so well. Saving my physics degree haha.

[@poporbit2432]

Can the polarizer be modulated? IE change the phase shift within it via electric, magnetic or mechanical action?

[@vishnubishnoi4621]

nicely explained

[@pc...430]

Hey, i really like your videos and I tried plotting waves in mathematica, but sadly it didn't work out properly. Could you upload the mathematica code? It would help me alot

[@jarredgrant1]

Came for the video, stayed for "what the fuck"

[@ishaankulkarni49]

WTH hahahaah. most unexpected thing ever.

[@sahilvedpathak9046]

Thanks a lot. Very helpful :)

[@meetoptics]

It is definitely 🚀

[@rajeshkumarb6226]

Great dear Jordan.

[@meetoptics]

Agreed!

[@megasharma2489]

Best explanation

[@ketyaportela623]

Thank you for your video. I'm a French student and there is no video of this subject in my language. Yours videos are very helpful!

[@meetoptics]

His content is so good.

[@julianklimke3476]

good explanation thank you sir

[@mtahirasam2447]

Jordan, Hope you will be fine. Can I get the mathematica file of this circularly polarized wave?

[@Edwinthebreadwin]

This is very clear :)

[@JordanEdmundsEECS]

Glad you think so! What made it clear to you?

[@manmohanbisht69]

Oops what the f. That was funny.. Nicely explained

[@Saptarshi.Sarkar]

Can I get the Mathematica code?

[@user-hm1nu3qg5g]

I like the way of your lesson. Thanks a lot!!!

[@meetoptics]

It is so good!

[@JordanEdmundsEECS]

Thanks! What do you like about it?

[@agrimmittal]

@@JordanEdmundsEECS straightforwardness :)

[@kihoy2k]

Hi, thank you for the tutorial. I have trouble understanding 8:12 when you factor out E0 and e^(jpi/2) the lower value becomes i, why not e^(jpi/2) ? Can you give some key words so that i can learn it from khan academy. Another question is where does that 7:03 k = 2pi/lambda come from ? Do you have video explaining it ? Sorry for the stupid questions.

[@sapphireempress5419]

Euler's formula gives e^i(x) = cos(x)+ isin(x). Since x= pi/2, the cosine function becomes zero while the sine function becomes one leaving only i. k is the wave number and that is a given formula of the wave number

[@whysoserious0609]

You are better than Kasap optoelectronics book!

[@sahhaf1234]

@10:15 No videos on elliptic polarization???

[@BeeDootube]

If anyone could help me, I have a question. I have to plot a circularly polarized wave and, if I'm not mistaken, the resulting wave is a combination of two waves E_total = Ex e^(kz-wt) x_hat ± i Ey e^(kz-wt) y_hat, where we have a real wave in x and an imaginary wave in y. Is that correct? If it is how can I plot the imaginary part? Because, as long as I know, this part will dictate the rotation and the shape of the wave.

[@jordanedmunds4460]

You're 90% of the way there. The trick is that you have represented the wave in phasor notation. The "real" (physical) solution should have only real-valued electromagnetic waves, so you need to take the real part of *both* the x and the y component. But isn't the real part of the y-component zero? No, because its phase rotates. Take z=0 and plug in different values of t. at t = pi/(2*w), the y-component is purely real, and the x-component is zero. The "real"/"imaginary" convention just makes it easier to do math on stuff and keep track of the relative phase (or physically, the offset or delay) between the x and y components.

[@BeeDootube]

@@jordanedmunds4460 Thank you very much! I'll try to do as you say and will be able to give you some feedback later.

[@pllagunos]

Damn that Mathematica plot is cool! Could you share it? I've been trying to replicate it, but so far I haven't been successful

[@KP-qk7jh]

this is fantastic! thank you, Jordan

[@caghey]

i couldn't find the elliptically polarized light video :(

[@CarlosRuiz-pt5ub]

I have a stupid question, why we multiply the J vectors for RHP and LHP by 1/sqrt(2)?

[@incianali]

I think that's to normalize the vectors. So, to make the length of them add up to 1. But I'm confused with the RHP light since the length would be 0 since i^2=-1 so 1/2-1/2=0.

[@incianali]

Understood it now: it's because we don't simply square it. We multiply it with the complex conjugate!

[@sophiavei1752]

can anyone explain the kind of polarization of (-i, 1)? (written in a column, of course, and without 1/sqrt(2). thanks! :)

[@luca3976]

thats also circular polarization, only that the electric field in x direction is delayed with lambda/2 to the electric field in -y direction. (i think.. xD)

[@sophiavei1752]

@@luca3976 thank you! That's what I thought too. It's just that there are so many variations on the way you can refer to it.

[@lebihkerendariTomCruise]

does anybody here know why dbi convert to dbic have to -3 db???

[@muhammadhamzashahid9649]

Please give me the code of wolform graph!

[@eugenetruman721]

Great explaining. Too bad there is no elliptical polarization video.

[@meetoptics]

It is an amazing explanation!

[@psyrene4894]

Why aren't you interested into the exp(...) part? Like I don't get it because withouth the exp(..) we just don't know thats its circular polarized cuz (1,i) ist just a constant and not a wave?

[@JordanEdmundsEECS]

It definitely still needs to be there, it’s just that dragging it around everywhere is kind of a pain. Once you’ve written the same thing 10-15 times it starts to feel unnecessary and annoying xD so by convention people don’t write it.

[@gergeselhaber4770]

5:25 HHAHAHHA

[@johnnybojan]

I lost it at 5:23, hahah

[@arfathq8069]

5:24

[@adityabaghel1270]

Amazing!!!?

[@Methoverbitches]

Me : sees shrimp punch hole in persons foot Also me : shrimp eyes do crazy thing Me now : how does my dropout ass understand this.

[@faisala.younus6223]

5:24 that moment when u question all reality and why you are in this world?

[@blugreen99]

All videos ignore how the magnetic field gets thu all polarizers horizontal and vertical. It tags along with the electrical component There is only wave not2 waves.......... 1 wave with 2 compnents inseparable.

[@jamesdennis6120]

Hahahahahaha totally caught me off guard lol

[@rebecasanzbarreras1715]

Si apruebo ondas electromagnéticas te dedico mi aprobado, pero como no lo voy a hacer te mando un abrazo

[@sl2357]

If you can't explain it simply, you don't understand it well enough. Albert Einstein

[@abuabdullah9878]

LMAO

[@mikemurrill01]

5:21 wtf?😂

[@collagetips7489]

if an indian teacher told that "what the fuck " it will be viral next day 😅😅😅😅

[@Kartoffeljoghurt]

Not pleased with the swearing, think of the children who are trying to learn about polarization and then have to hear this!

[@altaroffire56]

If they are intelligent enough to understand this, they are also mature enough to deal with swear words.

[@Kartoffeljoghurt]

@@altaroffire56 yeah, was just joking