Three polarizing filters: a simple demo of a creepy quantum effect
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- čas přidán 24. 04. 2019
- Crossing two linearly polarizing light filters blocks the light. But adding a third polarizing filter at a diagonal angle lets light through again, but only if the diagonal filter sits between the two crossed polarizers, not if it comes before or after them.
There's a good explanation of the physics here, where it's clear the filters actually interact with the photons instead of just passively reading their constant polarization.
alienryderflex.com/polarizer/
Because light is also made of photons, how exactly you can interpret what a filter does to a photon gets much less clear, and simple ideas like "A photon has a polarization" no longer match reality--the polarization you read depends on the filters you apply. Paul Dirac used this exact experiment as an introductory example to quantum mechanical effects in his 1930 textbook "The Principles of Quantum Mechanics", excerpted here: www.informationphilosopher.co...
These are the linear polarizing filters I bought (back in 2015, hopefully still good!):
www.amazon.com/gp/product/B00...
(Not an affiliate link, and I have no connection to this seller.)
I designed and 3D printed the red frames, and put the design files up here:
www.thingiverse.com/thing:496... - Věda a technologie
EDIT: As Orion has pointed below, this effect can indeed be explained through Quantum Mechanics. It just happens that EM wave theory can also explain this effect if we describe it using linear superposition of the polarization angles. However, while the EM version "makes sense" the ultimate complete explanation is quantum mechanical in nature. Thank you Orion for pointing this out.
Paul Dirac's 1930 textbook "The Principles of Quantum Mechanics" literally uses this exact experiment as an example of a quantum mechanical optical effect. An excerpt from his textbook (rather dense) is listed here: www.informationphilosopher.com/solutions/experiments/dirac_3-polarizers/
@@olawlor I have edited my comment above to reflect your answer. Thanks!
that's not dense, that's pretty smart actually ;)
@@olawlor
Yes. The peculiarilty isnt't that Malus's law occurs. The weirdness kicks in when we also learn that light is made of individual particles and that each particle can be fired at the polarizing filters separately. That is when logic breaks lol
@@jmcsquared18 was there any experimentation regarding polarized light and polarizers? Can we change the polarized light that it will got through something that it couldn't previously?
That was really interesting. Thank you Orion. This is a perfect example of why CZcams was conceived in the first place, for interesting, educational short films like this. Brilliant.
The paradox appears by confusing the function of a polarizer with that of a filter. Polarizers do not strictly filter (remove) components of the light, but can _add_ a polarized component to the light. If completely vertically polarized light hits the horizontal polarizer or vice versa, it is completely filtered. However, as it passes through the 45-degree filter, some of the light will be both horizontally and vertically polarized, making it survive the final filter. This perfectly explains why less light is filtered when the angled polarizer is placed in the middle, rather than the beginning or the end. You do not require quantum mechanics to explain this effect, so by Occam's Razor, it is the most likely explanation.
Well said
Interference, not filtration
@@mrknesiah Thank you!
damm you I was gonna point that out so I'd look smart. :p
"You do not require quantum mechanics to explain this effect" ok but how you do explain and calculate the polarizer "adding a polarized component to the light" without quantum mechanics. The way polarizers work and the mathematics behind them are deeply rooted in quantum descriptions of photons if I'm not mistaken
It's more like telling the photons come through the first filter to polarize diagonally, which isn't enough for the third filter to block them.
The other two filters combined with no interruption will always block all light.
So that makes sense to me.
It's easy to understand if you think the lens are "turning / twisting" the waves to the arrow direction. So when you put the third filter diagonally between the 1st and 2nd filter, you are just 'undoing' part of the turning the 1st filter did.
Exactly.
So the light is not blocked but realigned to some degree?
No, the filter is not capable of "twisting" the direction of polarization.
@@MirlitronOneThis is exactly what is happening. Polarisation filter absorbs a photon and there are two outcomes of this event:
-energy from the absorbed photon is dissipated as heat
-a photon with a polarisation aligned to the filter axis is emmited
The probability of these outcomes is given by malus law.
Ty for that explanation @@matbmp8996
I searched "three polarized filters" and this was the first result on Google. I was not disappointed.
An intuitive thought to make it less disturbing:
A pipe you send balls down, theyd get stuck on a 90 degree turn (assumed). If you add a 45 degree on that turn (so 2 45 degree) then their path is easily directed around the corner. If you place 45 degrees before or after in such a way as the 90 degrees is unaffcted they halt.
So it doesnt seem that counter intuitive, although they are not pipes and this does not explain the mechanics at work....disturbing? Doesnt seem so, not like a delayed choice quantum eraser or anything, what would be disturbing is if the order didnt matter!
This is a great analogy
Thanks for the video. I have always been fascinated by this effect. I will go and look at the link.
This is a simple phenomenon and easily calculated with same math for doing vector decomposition/projection.
Imagine you have an ice cube that is inside some rails that only allow it to slide from left to right, and another one in another rail that only allows it to slide back and forth (i.e. perpendicular to the first rail). If you throw one against the other, the other will not move, because the impact force is perpendicular to the direction it is able to move. But if you have a third cube in a diagonal rail, you can push the first one against the diagonal which will then slide with ~0.7 of the speed of the first one, and that one can hit the third one which in turn will slide with 0.5 of the original speed, thus able to "rotate" a force by 90º (but losing some of the power), where before it seemed impossible. This will not work if that diagonal one is the first or the third, same as we see in the video.
Let us assume, for the sake of argument, that, instead of polaroid filters, we are using black filters with a hole in the center, We have to put our eye close against the hole to be able to see directly beyond it. Rotating the first filter misaligns the hole relative to the hole of the second filter, showing us, besides the scene directly behind the first filter, the black and opaque surface of the second filter.
If we now put a third filter between the first and the second, at 45 degrees, still with our eye against the first hole, we are able to look through the hole of the third filter, at least partially, all the way through the second filter and beyond.
The experiment of polarization is best done using microwave, since you can see the physical structure of the polarizer. In case of three polarizers, we can demonstrate that the light coming out from the diagonal polarizer has diagonal polarization state. By turning the third polarizer in line with the second polarizer, you'll get brighter light compared to when it's vertical or horizontal.
I've made many videos investigating behavior of microwave transceiver here in CZcams. I conclude that objects interact with electromagnetic wave following the same rules as how radio antennae work.
I put my sunglasses in the microwave oven. It melted.
Just kidding, this is all extremely fascinating. I just wanted to make a stupid joke
i kind of expected a muslim to give a reasonable reason, instead of the obviously bullshit quantum theory. cause they never show the instrument they use to emmit a single photon, and the other to detect it. there is no video of it. I guess like all the bullshit in the world, quantum shit and light having finite speed is another of those bullshits created so that muslim and islam could shine. wonder why the world pretends to be jew, christian, hindu, scientist, liberalist, black, gay... when literally every one is a secret muslim working with the goal to make islam/muslims shine.
Really deep and interesting stuff!
Do you have a link for the filters you use? (Just find some filters without the practical plastic frame)
I printed those filter frames, and just posted the STL and OpenSCAD to Thingiverse here: www.thingiverse.com/thing:4967649 Enjoy!
Thank you so much
Here is explanation for casual brainer. Basically everything around you (energy, matter, etc) only "rendered" when they are "interacting". If not, they are just "wave function". A chair is only a chair when you sit on it.
Now what happen in this video. The light that travel throught filter needs to interact and choose how to proceed. So 2 polar lens that is opposite in polar cancel each other. Making the object looks black.
Now by having 3 polar lens at an angle. The middle lens is basically tell the light to choose pass or not, making the light "change" polar properties. Therefore, 3 filter have more light than 2 filter, because the middle filter force the light to interact and "choose" (Aka become particle) at an angle.
This is the weird thing about quantum theory. We might as well call our world simulation at this point
Where can I purchase these filters please?
These are the linear polarizing filters I bought (back in 2015, hopefully still good!): www.amazon.com/gp/product/B004X3XFHU/ I 3D printed the red frames, and put the design files up here: www.thingiverse.com/thing:4967649
It’s not creepy to me, i find it magical and awesome!
The 'Three Polarizing Filters' experiment is the BEST demo of quantum physics.
I would enjoy hearing anyone explain how this works; where the hoi polloi (me) could understand.
The first principle is that you must not fool yourself and you are the easiest person to fool. - R. Feynman
Light is a wave that oscillate
@@Funkeditup , light does not "move" the way you are assuming. It's a wave, always propagating omnidirectional.
When you place those filters there, it's no different to placing a pair of rabbit ears on your TV, and adjusting them. The signal gets stronger, weaker, to the TV, (analogous to your eyes), but just because the TV has a weak signal, doesn't mean anything for the electromagnetic wave that is bouncing and propagating all over the room.
Those filters are causing constructive and destructive interference to an electromagnetic wave. It's just like how a radio signal that cannot be heard because it is too attenuated (weak) can be made strong again by using a yagi antenna. The yagi causes constructive interference to the wave, which increases it's power. Same thing your filters are doing to the light. Your eyes are akin to the radio receiver. Light is just the sliver of electromagnetic spectrum that our brains assign color to when it interacts with other matter.
@@Funkeditup call it what you want. It's functioning as I said. It's attenuating and then amplifying the electromagnetic frequency the same way antennas and other metamaterials do.
If you truly want a shocker, perform the quantum eraser or dual slit experiment above visible light. You'll find that the photon is pure hypothetical conjecture. Everything is waves, otherwise you run down a reductionist rabbit hole of particles, and always end up with the glaring problem of what's in between these particles. What's "waving"?
czcams.com/video/3YHaWHwJHWo/video.html
@@Funkeditup yes, polarization. Have you ever transmitted RF (same thing light is) out of a vertically polarized antenna to another vertically polarized antenna, and then changed the RX antenna from vertical to horizontal? The signal drops significantly. This is what's taking place with the light. You're removing portions of the "signal" to your eyes. If you could see a bright color at 440 mhz, and you held a resonant yagi antenna in front of your face, and turned it back/forth while a broadcast signal was traveling towards you, the "brightness" would change. Sadly no one can see that low in frequency, because if they could, light would not be so mysterious. It works exactly the same.
@@Funkeditup I don't assume you know nothing. I'm merely giving you (and others) another way to look at.
I love when people pretentiously confuse description with explanation
I don't understand your comment; no one is explaining the effect here. 🤔
Hello, how much do you estimate the visibility rate when you put the 3 polarizers?
50% according to EM wave theory
@@alexroznowski9376 can you explain this phenomenom ?
My mind says it’s just bending the light between the horizontal and vertical to be in between, diagonal, but once you block the light with sequential filters the light has been stopped already.
The "quantum" part is not to see light as only photons. QED has taught us that they are both wave and particle, or neither. Quantum field theory, Feynman, .....
Best way to think about it is in a probabilistic wave approach, rather than a deterministic. Which then explains the "why" behind the questions asked. Their probability (i.e. the probability of light/photons passing through) concurs with light intensity passing through as shown in these experiments.
I only think of the probabilistic approach as math that works but not reality, I mean in the end, the photograph you take is determined from the camera itself.
You are not asking the photons questions as he says, nor do they chose anything. I like to think of them as "flying tomato juice" lol. It can start concetrated as a beam, spread out like a wavy fluid and how you will stop or interact with it will affect its properties. Catch it mid air with a cone it will become like the shape of the tool you used.
Spooky and bullshit.
It's easy to think of it as deterministic so I don't see why not. I'd argue thinking of it intuitively with an actual mental picture you can have in your head is a lot better than vague wishy washy things that nobody actually understands or visualize. I feel like there is an explicit effort when it comes to quantum stuff to make it as unintuitive as possible even when the unintuitive stuff has nothing to do with the actual math but just stuff people make up and insist it makes more sense but then will say themselves they don't even understand it.
quantum efect; 1) first filter vertical: only vertical polarized photons pass 2) filter diagonal: 50% of diagonal polarization pass 3) filter horizontal: 50% of horizontal polarization pass from diagonal polarized photons.
Tapered cork screw effect of q wave?
Nice name! I love physics too, what a coincidence
Was there a reason that you could not put the camera on the same level as the filters?
I'd be more creeped out if the effect was happening when holding the filter between the camera and the two standing filters.
use polarized filters that reflects 50% of the light on one side, it may not get the same affect, I think polarized filters breakdown the field, the filter in between merges the field.
I think it's due to directional waves...the small change of degree the transferability of photon will get through...Whereas the large sudden change will put to halt.
i think there is a common sense answer that denies the unique 'strangeness' of the QM explanation. If we replace 'filter' with 'how easy is it to twist' then instead of
What percentage of light is 'filtered' by a polariser at angle x, we ask 'what percentage of light is twisted by a polariser at angle x'.
To twist light 90 degrees is not possible with one polariser, because it is impossible to twist light 90 degrees with one polariser.
But it is possible to twist light 90 degrees with 2 polarisers, because any angle less than 90 degrees is possible to twist with one polariser. So long as our 2 polarisers have a combined twisting of 90 degrees, but each is less than 90 degrees .... then no surprise.
Its like saying "If i cant twist a screwdriver 180 degrees with one twist, then i can break it down to 2 twists". The most efficient would be a half way to the desired twist angle for both twists... ie 90 degrees for the hand held screw driver.
So similarly .....for polarisers that are not capable of twisting light 90 degrees in one go .... then use 2 polarisers instead .... with each twisted at 45 degrees, to be the most efficient light twisting of 90 degrees using 2 polarisers. (2 equally difficult twists)
looked at this way there is no mystery at all. We use screwdrivers all the time and and we dont grab hold of the handle and run around in circles. We break it down into multiple twists. But the reason we are tricked into thinking the polariser filter paradox is strange is because we think of filtering ... not twisting. If they were called 'polarising twisters' we wouldnt be surprised by the effect at all.
These are linear polarizers, which do filter, not the circular polarizers which do in fact twist the polarization though. And the paradox here is that the *order* the polarizations get applied changes the answer, which isn't the case for 2D rotations.
@@olawlor yes... but with respect you missed my point. linear polarisers are neither 'twisters' or 'filters' in the common sense use of those words. But if you use the common sense view of a filter, then the polarisers as filters yield the strange result that "2 filters can let more through than 1 filter" or "3 filters can let more light through than 2 filters".
In common sense language this is 'strange' wrt to filters. BUT if you replace polariser (linear) with twister .... then it makes perfect sense.
ie the language of common sense can be used to show combinations of polarisers as "weird" or "normal" depending upon whether you describe a polariser as a twister or a filter. A polariser is revealed to be neither in the QM sense, but usually gets translated to 'filter' in common language for obvious reasons. Yes you can see them as 'filters' .... but we can alternatively see them as 'twisters' too.
What this shows is that language is not passive! Filters appear much more passive than twisters. But that is appearance only. Filters as language are as non passive as twisters. Unfortunately we are tricked time and again into thinking language is passive and not active.
@@feelthewyrd I really like this explanation.
@@davidgervais5974 thanks. i have studied QM but i cannot defend incorrect mystification. QM is strange and surprising ..... but when a common sense expanation for a QM phenomenon is there then dont dismiss it or jump to a deliberately 'creepy' one.
It is easy to forget that newton shocked the phyics world with his explanation for gravity as 'action at a distance'. When einstein spoke of 'spooky' action at a distance re QM ... it undermines the idea that ANY action at a distance is 'spooky' or 'creepy' to a rational materialist.
On the other hand there was a materialist explanation for newtonian gravity available that was not 'action at a distance' ...............but newton and his contemporaries missed it. Just like most people miss it for the polarisers.
different lighting set-ups and use a laser pointer...
I thought you can explain this phenomenon by the wave nature of light.
How?
@@664theneighbor5 on the assumption that by passing through the filter, the em wave is modified by it, causing it to become aligned with the filter polarisation, with amplitude proportional diminished
Could this be used to make a secure device screen that will appear black to onlookers but dimly lit to someone sitting still wearing glasses polarised to the correct angle?
The problem is if you just had the first horizontal polarizer and the second diagonal one on the screen, then it would allow light through to anyone around. This issue arises as you would need the specialised glasses to fit between the two filters in the screen to get the desired effect you're talking about. Would be a neat idea though if there were a way to make it work.
Yes ,its been done 👍
@@Arun-yl8kc Would love to see that.
@@Baggytrousers27 czcams.com/users/shortsjzY-N7V__fU
Another idea would be multiple images at different frequencies. A screen can redraw an image many times per second, usually at least 60fps. If 59 of those frames are black but one is data, you could devise an optic that filters for that single frame, while the screen just looks black to naked eyes. I think in theory you could have 60 different images all being flashed on the same screen that could be isolated by that many different optics.
Thumbnail literally felt like the video was a render
Seen this plenty and lots of people reckon they can explain it.
But no explanations that I have seen make sense.
It actually defies all theories of light,
including QM and wave-theory.
This experiment does not make sense if you're under the false impression that light is made of solid particles referred to as photons. Which is impossible for a solid particle to pass through anything else without evidence such as a hope through the glass. Light is not a particle as proven by this experiment. Except the so called experts have confused the masses with all this theoretical quantum mechanics THEORY on top of THEORY to disprove scientific fact and LAW. Light is an electro magnetic induction wave and any experiment will only prove it to be such. I get so frustrated with these theories being used to over ride fact. So absurd how many buy in to this word theory
It's very simple: what you are seeing is the light that comes through the final lens. The first lens changes the light so that it cannot pass through the final lens. The second lens, put in the middle, changes the light that comes out of the first lens so that it can pass through the final lens.
@@customsongmaker I think what blows peoples minds is they cant think of the polarization as something that alters the light. I also wonder if distance makes a difference and if that changes with color filters.
Search on CZcams: Polarization of photonic light journal.
God I love this. I have actually won a bet with this effect.
I have discovered a truly marvelous explanation for this, which this comment field is unfortunately too narrow to contain.
So apparently to solve this we got to assume we live in a simulation and there is a background system that is rendering out world. Much like a game being rendered by a computer in real life.
What happens if you shine a high powered laser through it? Does it diminished to nothing too?
That'd be interesting to try! The filters aren't perfect, so a small amount (a fraction of a percent?) of the light still comes through even with the filters at 90 degrees, so I think a bright laser might still be visible.
And a powerful enough laser would melt the filter!
Isn't it possible or likely that each polarizer is polarizing the light with itself? For instance, 50% of the light makes it through A. B is 45 degrees to A, and each photon has a 50% chance to be polarized now to a 45 degree angle. C then is 45 degrees to the incoming light, and we reapply the 50% chance to repolarize. In the end, we should end up with 12.5% of the incoming photons, all of them polarized in the same direction
People thought this but when you shoot a single photon, you still get the same behavior.
its not complicated if you just think about it.
Ever try wearing polarized sunglasses beneath a motorcycle helmet with a polarized visor? It's pretty weird, especially when you turn your head.
Hmm, I think photon is the paid actor!
dopeeee
The diagonal filter can't unblock sunlight that never gets to it.
Make it 6 time to see what happens. If you have enough filter maybe you can get down to only.one photon.
this isnt possible to find out. photon isnt a particle. it isnt a wave
@@krishnarathi3420 light is a wave made of particles.
I don't think that's a quantum effect. Doesn't it have to do with the direction the waves are passing through? So you change the angle by changing the location of any particular filter.
I woke up this morning thinking about this experiment and using it on entangled photons. It is always said that you can’t use entanglement to communicate faster than light because you cannot “know” the polarisation of a photon until you measure it, and then it is destroyed and so if you measure its entangled twin, it won’t allow you to infer any information about the other photon. But it seems here, that you can actually change the polarisation of a single photon by using several polarising filters. Surely, this method will allow you to encode information in the polarisation, and hence in the polarisation of the entangled twin, and so “communicate” (I know it’s only a kind of synchronicity) faster than light.
So a gradual change in angle from filter to filter (instead of a sharp 90° difference) allows light to pass through.
While a stark difference in angle blocks it.
Kind of like a flow of water, if gravity wasn't that much of an influence.
The so-called paradox is also easily demystified simply by changing the order of the polarizers. In order of appearance
A horizontal
B at 45 degrees of A
C vertical
The end result will be exactly the same as with the "paradoxical" setting whereby C is slipped in between A and B, but without first turning A dark and opaque.
Somebody not present while the polarizers were being set up would never notice the difference, since there is none.
Get something to do
is this a malus’s law?
Malus's Law can indeed be used to describe this behavior, where cos²(90 deg) is 0 for two polarizers, but cos²(45 deg)*cos²(45 deg) = 0.25 for three polarizers.
Interesting topic but incomprehensible speaking !
this isnt a quantum effect. Iits just a normal vector component effect. you can get the same dffect with forces (which are also vectors). if you pull something up it wont move sideways. if you pull sideways is wont move up. but if you restrict the movemend in 45 degrees you get a movement sideways when pull up.
I so sorry it hard for me understand but I want to understand this :(
i have a idea that ur massaging the waves into a spin
Why this always confuses Simple-Minded people Is because some commenters think light is a particle and some commentors think light is a wave. well, it's neither, Light is a coaxial perturbation of the aether. It is neither a particle nor a wave. Light does not travel. It propagates, there is nothing moving from here to there. Nikolai Tesla said "Light propagates through the aether the same way sound propagates through air." The speed of the action is dependent on the medium that it's propagating through. Light propagates at 186,284 mps. That is the rate of induction of the aether. Sound propagates roughly 1100 feet per second in air, at sea level. Through water, sound propagates many times faster, through steel, sound propagates at 85,000 ft per second. So you see, it's all dependent on the medium. Light and sound are nothing more than compression rarafaction events of a medium, Frequency specific.
You're welcome...
.
No, you're not asking the same question each time. In 3 of the arrangements, you're asking "Can I see horizontally-filtered light through the vertical filter?"
By putting the diagonal filter in between, you're changing the horizontal light to diagonal light. Then the question becomes, "Can I see diagonal light through the vertical filter?"
Precisely! Spot on. I don't understand why this was ever a spooky thing? To me this gives more definite answers than raising questions. It's like pushing a coin in a coin machine slot.. at 90° Angle, one can never push through,. but a 45 or less angle, the coin will find its way by twisting due to the push. And another 45 will do the same. So the coin that can't go through at 90° slot differences, can infact go through if you insert a 45° slot in between that actually assists the penetration.
@@Hasan... The spooky part is that asking the question changes the photon's later answers. With entangled photons, asking *later* questions changes *previous* answers about its polarization. If you give up the notion that "reading a particle's polarization" is even a thing, as you say it does get less spooky.
@@Funkeditup I also started from the minute physics video, searched around and finally ended up here. The accurate explanation in the link in the video description made everything much more clear!
Support your ans brother
I don.t agree with your secnd statement. If a horizontally polarized light passes through a diagonal filter that is not obvious that it becomes diagonal light, but if a non polarized light passes through a diagonal filter then in this case it is obviois that the output is a "diagonally polarized" light (and i use double quotes because i think there is no such thing as a diagonally polarized light)
We can also do this with two sunglasses too?
Yes! Most polarized sunglasses use linear polarization, so crossing two lenses at 90 degrees indeed looks very dark, and you get the three polarizing order-dependent weirdness if you use three pairs.
@@olawlor ohk thanks 👍
Glitch in the Matrix
We all searched for this… didn’t we?
If your are a positive person you will get a positive answer.
If you are a negative person you will get a negative answer.
If you are unsure you will never be sure of your answer.
The power is in the question not the answer.
👏👏
QuAnTuM EffeCt
Portal 3 confirmed...
Kant noumena
This is just the consequence of Malus' law, there is no quantum effect involved.
You might want to take that up with Paul Dirac, see the textbook link in the description.
Imagine looking through a periscope but all you see is darkness. Then you realise one of the mirrors is missing. You slide in the missing mirror and now light is able to pass through the periscope. That's similar to what's happening here, just easier to comprehend. Nothing is spooky or magic when you understand how it works.
You also don’t get it do you?
@@ronaldoquintos1675 Fine, it's just fucking magic
Sorcery.
Yeah no shit.
having my own personal views on how light propagates, i cannot accept a transverse wave as even being possible... i only ever see transverse waves on the SURFACE of things. at the junction of two media, where one is free to oscillate in the other... and in doing so, will produce perpendicular compression waves in the OTHER medium. i have never seen any example of a transverse wave propagating THROUGH anything.
it has been demonstrated with ultrasonic arrays that sound can be "beamed", much like a laser... you cant detect it at right angles, its passage. only its interference with something... "theres the red dot" versus "theres the sound"...
a lightbulb sprays light everywhere, as does a loudspeaker... we can manipulate both with reflectors, parabolas...
to me, this relates back to sound, and the fact that when we "see", we are using an array of tiny sensors that are still LARGER than the wavelength they detect, and further apart...
whereas when we HEAR, we use a SINGLE (pair...) membrane that is far SMALLER than the lowest wavelength it detects...
but also, just as importantly... the way the... "impulse" is created in the first place!
why do i see colours with plastic, a change of FREQUENCY, but plain polarising filters are always just... filters? they filter ALL wavelengths, not selective ones...
the "rule" that one cannot "polarise a longitudional wave" aka compression wave was "determined" before we had amplifiers, microphones, speakers, radio...
i havent seen anyone challenge that theory... and thats what it is.. a THEORY.
All it does is finish the rotation.
Polarization is a wave phenomenon. There is nothing quantum about this demonstration. When the 3rd filter is placed between vertical and horizontal filters it repolarizes the light from the vertical filter and transmits a component of that light (the cosine) to the horizontal filter. That 45 degree polarized light is then repolarized by the horizontal filter and transmits a component of that light. There is only 100% blockage when the light passes directly between two filters that are at 90 degrees. (like when the 3rd filter is first or last in order. Any other combination allows some light to transmit. Photons don’t “know” or “hear” anything. Anthropomorphizing photons is not helpful and leads to discussions of “consciousness”.
The question here is how to understand polarization from a particle perspective, not the wave perspective. Photons indeed don't know or hear anything, but their behavior in a filter lets us 'ask questions' about their polarization, and the results tell us something interesting about quantum measurement (see description).
I don’t comprehend the logic of your demonstration, as to why you are disturbed. As what a comment mentioned, the sequence of polarisers is the key fundamental issue. Explaining in layman terms, a polariser only lets light pass through along its axis of polarisation. Basically if two polarisers are crossed, i.e. their axes of polarisation is 90 degrees or perpendicular to one another, no light will not be able to be transmitted beyond the second polariser since cos90 =0 (you can apply Malus law for polarised light where I =Iocos^2θ). So if you take a third polariser at axis 45degrees and put it in front of the two crossed polarisers, no light will be transmitted beyond the last polariser since the issue here is that there are still two consecutive polarisers in crossed alignment. Even if light were to be polarised by 45 degree, the two consecutive polarisers will eventually result in cos90 =0. Same effect if you placed the 45 degree polariser as the final polariser - no light is transmitted since the first and second polarisers are still crossed so there is already no light to be polarised by the time it reaches your 45 degree polariser. So the only way to let light through is to put the 45 degree polariser IN BETWEEN the two crossed polarisers so that a component of light can be transmitted (Icos45 in this case). This is a typical physics problem involving three polarisers. Look it up on CZcams.
I'm baffled as to why the presenter and the commenters are giving the effect shown in the video a quantum-weirdness interpretation. The latter only starts to pertain when we come to the case of single-photon emission.
The weird thing is that these are not filters, like I and also OP thought at the beginning. A filter means that only light of a specific polarisation gets through and the rest gets blocked which is not what is happening here. In this case the filter changes the polarization of the light passing though or the polarisation gets specified in that very moment (the wave function collapses). So the light basically has no polarisation at all before it reaches the first filter because the wave function did not collapse yet.
So calling those things filter is wrong because they don't filter the light in a sense that we would think in the "normal" world. For people who don't know these properties of light it is fascinating.
Before I watched this video I thought that the sun created light polarized in all directions (360°) but now I know that that's not true. The sun creates light that has no polarization at all, like it does not exist until you observe it.
This is a result of polarising filters not being “perfect.” Nothing more.
Light is an electromagnetic wave. Same as all other RF, and behaves the same way, but has much smaller wave scale. This is simple constructive/destructive interference. There's no magical woo woo taking place here. Same thing happens when you use a yagi antenna at lower wavelengths, and put it in your living room. Only difference is, your eyes/brain don't assign colors to it as it interacts with matter. So you cannot "see" it, but you can use a radio transceiver to "view" the exact same effect.
Radio tower transmits signal. Signal strikes various objects as it propagates towards your house, and then it passes through the walls of your house, causing destructive attenuation of the signal. Then, when that now weakened signal strikes the yagi antenna inside your home, it can be constructively interfered with itself to increase the signal. If the radio signal was transmitted only vertically polarized, and you turn that yagi horizontal, you'll lose half the power roughly. Turn it vertical, and magically the signal gets strong again. Most radio stations transmit their signals both vertically and horizontally to account for this, and this is how light is too (circularly/vertically/horizontally polarized depending on source). Quantum nothing. It's just how electromagnetic waves work. There's no magical BBs of light being stopped by those filters, or passing through them. It's an induced wave. It's components are already on all sides of those filters, and moving omnidirectional.
I agree.
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I think that happens because light enters from the sides also. If these lenses were in a tube there would be no extra light to influence your answers.
I understand nothing.
The difference between the two explanations in the description is hilarious. Quantum physics is a joke I swear to god. I mean obviously there is a lot of real and good science in quantum physics but there is so much gobbledygook in how it is conceptualized and talked about.
WTF, are you talking about. He explained this Bell Experiment perfectly and quantum physics is the most proven scientific theory we have. The fact that you’re able to see this comment for example on a screen with your phone or laptop proves that not only by the polarizing effect of the screen but the billions of quantum electrons it’s using.
Hmm... Wasn't it Richard Feynman who said something along the lines that, if you think you understand quantum mechanics then you haven't really grasped it?
@@cassianomota8574 "quantum electron" is the exact kind of nonsensical phrase I would expect from a CZcams comment reply guy defending this.
@@andrewg3196 "Quantum mechanics of electrons" FTFY. Try debating the argument instead of focusing on senmantics there smart guy. You'll get further. 😉
Could the explanation and think about Einstein's words "I like to think the moon is there even when I am looking at it" means that there is some kind of universal conscientiousness is always looking. Know what I mean? That God is spooky?
Nothing quantum is here. And nothing creepy or weird. Can be easily explained with classical theory of light or electromagnetism. Can be easily explained in the normal framework of QM without any weird stuff or creepy stuff. Not a quantum effect at all, at least not more quantum effect than me swimming in the sea.
I agree Maxwell's equations explain this easily, but are incompatible with the quantum view of light as a stream of photons. Paul Dirac chose the three-polarizer experiment as an example in his textbook "The Principles of Quantum Mechanics" (link in description).
@@olawlor The practical incompatibility detail is that a single photon is either absorbed completely or passes completely the polarizer - which your experiment does not demonstrate. On the other side, after passing a polarizer, a photon has a well determined polarization state which is pretty analogous to the polarization state of classical light - which allows a simple explanation of this experiment both classically and quantumly from nearly the same principles. In other words, while a state of a single particle has very different description in classical mechanics and in QM, the polarization state of a single photon in QM is pretty analogous to the polarization state of light in classical physics. That Dirac chose this experiment to consider quantum effects is not more instructive than if he chose Archimedus law to review it from quantum positions. Bottom line, while a light beam (consisting of very many photons) is used, no quantum effects are seen, nor predicted, nor any sort of weirdness demonstrated. No "creepy quantum effects" demonstrated.
@@michaelpodolsky1368 This experiment demonstrates a key feature of quantum interactions--that passing a filter *changes* the polarization of photons. Prior to understanding this experiment, I had interpreted a polarizing filter as *reading* photon polarization and stochastically absorbing photons based on their angle mismatch, which this experiment conclusively disproves. The quantum effect here is that photon polarization is also *written* by the filter, and in fact there are no "read only" filters, and even the concept that "a photon has a polarization" gets slippery, which I find illuminating though a bit unsettling.
@@olawlor usual radio wave + a grid of wires does the same job changing the polarization plane of the passing radio wave. That I am now sitting at the table is also a completely quantum phenomena, but I would not say it demonstrates anything quantum. That the radio wave passes a wire grid changing its polarization or light passes a polarizer changing its polarization or a coin changes its orientation when pushed into a slit - does not demonstrate any quantum effect or quantum weirdness either. How the polarizer works is a well established knowledge _outside_ of the quantum theory. If some people misinterpret it or do not have this knowledge - this does not establish any weirdness or creepiness for the phenomena.
@@michaelpodolsky1368 Polarising filters for light work in the same way as for radio waves, which is unsurprising. Light is an electromagnetic WAVE, but it seems many science communicators ignore this.
Stopit
Not everything is associative man. We have seen a lot of examples in mathematics. Why it seems weird to you. This is simply not associative.
Rather it is commutative.
Each polariser act as an independent source which is followed by Huygens' principle.
I so sorry it hard for me understand but I want to understand this :(
@@abusopyan4290 reply here your email. I will send you my hand made notes so that you can understand easily.
This effect has been understood to be quantum in nature for nearly a century…
This intuitively makes sense, think of it like a percentage of light being filtered; percentage wise the first polarizer removes 50% of light, the second polarizer at 90 degrees from the first removed the other 50% reaching 0% light throughput. Adding a third in between at 45 degrees removed only half from the first 50%, giving 25%, then the third acts as the first polarizer resetting the wave direction, passing fully through the last one.
It is not creepy ... that JUST how it works!
sus
That's because the middle polarizer has shifted the angle. There is nothing odd or strange about this. What you just did is deterministic and not random. You are getting the same results every time. You need random answers for this to become a quantum effect. Because quantum mechanics is essentially obsessively using probability and statistics to small scales where both position and time of atoms cannot be known simultaneously.
A polarizer simply pass through light wave wiggling in one direction and blocks out the rest. It does not “twist” orientation of light wave like you are describing 😂😂😂😂 I don’t think man has figured out how to do that yet ahahahaha😂😂😂. You are describing a polarized as some kind of magical device that can “twist” light 😂😂😂so funny you make me laugh
When a single photon interacts with a polarizing filter, its polarization state is quantum-mechanically described by its wavefunction, which can be in a superposition of different polarization states. As the photon passes through the filter, its quantum state evolves according to the principles of quantum mechanics.
The behavior of photons in a series of polarizing filters, as described by Malus's Law, can be understood in the context of quantum mechanics. Quantum superposition and the probabilistic nature of quantum measurements are key elements in explaining how individual photons may or may not pass through each filter based on their polarization states and the orientation of the filters.
I think you have no idea what’s going on here from your “pppfff nothing weird here” comment
This just shows wave-particle duality of light because the momentum of light(particle) is changed when it hits the middle filter. Only a fraction of light will change vector to align with the third filter, which is why it’s dimmer with the middle filter.
are you trying to say that you know, while the science world has no idea to explain it?
Uhh... I think you may be confusing 'probability' with 'random'...
QM is about randomness only insofar as it is a distribution of probabilities. (The math is a bit confusing, but the concepts aren't, and a misunderstanding of one can make the other difficult.)
Still, it's good that you're interested!
it bounces off the diagnoal lines at an angle that allows it to penetrate the vertical polarization...if this is real
Lets have another example.
Pass a light from a circular hole of radius 5cm and then another hole in the sequence having radius 0.5mm.
Now reverse the order. Did you see the same result, the same intensity of light?. ofcourse not. Sequence matter here. What is weird here? Nothing. Use another punch hole of radius 2cm. Keep shuffling them. See yourself. Will not get same result in every case. Asking questions in defferent sequence are not same, sequence actually matters.
This is not a good analogy. Because the effect we observe here will hold true for a SINGLE photon also. The measurement will collapse the ultimate polarization. In your case a single photos will behave exactly the same in both cases. Therefore, it is not the same situation.
@@Thesignalpath how can you say this is true for a single photon. In addition to that. I was just trying to say this is not weird in contrast to the claim in this video. Do you think this phenomenon is weird? See my other comments to know clearly. I have mentioned Huygens principles to explain my opinion.
@@surajpatel3044 The single photon experiment would be similar to the double-slit experiment and would have to be explained probabilistically. Unless you can explain what would happen with a single photon in this polarization experiment. Furthermore, what I or anyone else thinks is “weird” is entirely irrelevant. What matters is what the physical, real explanation of the observation is. The theory should explain the observation with a single photon and many photons.
@@Thesignalpath ok I got it. First of all I need to study in detail about single photon experiment. May be there is something that I don't know. And I really wonder if it is even possible to create only a single photon in practical.
@@Thesignalpath I see you have a an amazing CZcams channel. That's great.. 👍🏻👍🏻 never expected that. Good luck for future videos..
So you can't explain it either! 😂
Interesting visual but terrible explanation. There are much better out there...
It frustrates me so much that people call these things "creepy" or "weird". No, it's creepy or weird just because you don't understand what's happening and want to attribute everything to "magical quantum mechanics". That's not a scapegoat for being uneducated.
This isn't a "quantum effect", it has nothing to do with "asking questions" or "getting answers". You aren't "asking photons questions". What a moronic thing to say.
Educate yourself.
Take this up with Paul Dirac, link in description.