This video was such a joy to make. Thanks again to Craig Newswanger and Sally Weber for showing us the ropes. Two mathematical corrections: 1) In the analysis at 26:10, we should do a Taylor approximation about d=0, not about x=0. If you this right, the result at the bottom will look like x / sqrt(L^2 + x^2), which conveniently cancels out another (much sillier) mistake, which is how x / L in this case is not sin(theta'), but tan(theta'). Thanks to those who spotted that, I guess I must have been happy enough to see the desired sin(theta') at the end that I didn't properly double check how we got there. 2) In the end, I referenced treating |R^2| as "some real number", so that it's only scaling O. This only makes sense to do because the amplitude of R is constant. Or at least, it varies only very slowly around a point. In this way, what I say a few moments later about making no assumptions about R is not quite right, we do need to assume it's a wave with relatively constant magnitude across the film.
I was always told that any part of a hologram contains all of the information in the hologram as a whole. This gave me such a better understanding of what that actually meant and how it isn’t entirely true (in the way that I was thinking about it). Thank you for these amazing videos!!
26:31 A potentially more elegant way to reason through this is: the two distances shown in 14:58 have to be destructive at each black point. this happens when D and the distance of that other line to its right. The way of finding these distances and angles between the two lines functions THE SAME WAY we did in the section “Diffraction gratings”, so we end up with the same formula. @3blue1brown
26:31 A potentially more elegant way to reason through this is: the two distances shown in 14:58 have to be destructive at each black point. this happens when D and the distance of that other line to its right. The way of finding these distances and angles between the two lines functions THE SAME WAY we did in the section “Diffraction gratings”, so we end up with the same formula. @3blue1brown (I wrote it twice to get your attention.)
I didn’t do any formal analysis to justify this, but: the image you see when you flip over the film to look at the conjugate image doesn’t look like a weird distorted version of the original to me - I think it looks like what you would see if you were inside the original scene looking out?
@@HankMeyer You should remember all the times a teacher or tutorial just skipped over a step you wanted to know more about and understand Grant doesn't do that and it is a very nice thing on this channel - he gives you the full picture If you want to skip over you still can - so yeah. Skill issue
Without question, the best video on how a hologram works that I have seen in my 42 years of making holograms. What’s more, I made one of the three holograms shown at the beginning of the video in the living room of my first house in 1986-87.
@@3blue1brown The hologram portrait 'Lucy in a Tin Hat' was shot by Royal College of Art holography student Patrick Boyd and I whilst at the RCA in the mid-1980s (the first Master of Arts holography course in the world). As one of the three founding members of staff of the RCA's holography Unit, I designed, built, and operated the RCA's pulsed laser hologram portrait studio, but operated my own private holography studio at my home at the same time. I would often take the student's master holograms home to shoot the reflection hologram copies at my studio during the night for maximum brightness, as the stability in my living room was far better than at the Royal College! Stephen Benton, inventor of the rainbow hologram, often told me that it was the best hologram portrait he had ever seen. The Microscope was of course by Dutch holographer Walter Spierings. I particularly liked your use of a single-point Fresnel zone plate, followed by multiple points and thus overlaid zone plates to explain complex holograms. I use this method myself but have not seen it in a video before. The visualizations and graphics are incredible. Again, well done.
@@3blue1brownHey check out my new beautiful equation. X²*X²*X²*...♾️ < X³ this is a simplified version... Think about it, a square is two-dimensional meaning length and width only with absolutely no depth... A cube function has depth... If it has depth then that means infinite amounts of two-dimensional existence can stack into any size three dimensional existence... Thus this equation is fundamental. Yet another mathematical shattering of the status quo. ² means squared ³ means cubed... This solves so many problems with math and creates a lot more maybe.
At 11:40 I genuinely was so surprised by what I was seeing. I had no idea this was even possible. It literally looks like you’re looking through a portal to another world. Light is so cool!
This is the most beautiful hologram class I ever have. 30 years ago, I produced my first hologram in the optics lab of the university. It was a real magic, but to this artwork, I only catched very fuzzy realizations from the vector equations in my textbook. That was an era without internet and youtube video. Thank 3b1b, guys that helps production this video, and the astonishing IT technology, to give me such a deep and visualized unstanding on hologram!
Just as an addendum about the astonishing IT technology behind Grant's videos: it's actually all programmed and mathematically correct. He writes hundreds of lines of Python code for all his videos. He wrote his own library and improves it for his needs.
As a rare hologram (REAL ones) nerd, this might be my favorite video on RUclips of all time. Your simulations are always so beautiful, and getting to see those museum pieces was incredible
11:39 This feels like it would make an incredible element in an escape room. Have a table set up, and to solve the puzzle you need to find these chips with different scenes recorded on them at the same table
This would be incredibly cool, but I fear that these disks would likely get lost easily, get damaged or possibly stolen too. And judging by the delicacy of the process, it's likely not cheap either. So yes, amazing idea, but most likely impractical.
I'm a high schooler who couldn't attain a tenth of your mathematical knowledge if I tried, but I still frequently find myself returning to your channel. It's not something you can exactly verbalize, but it's clear that you're an accomplished educator who can take complex and out-there ideas and ground them in basic logic and understanding. I'm frequently blown away by a channel my dad watches. I need to stress that - my dad watches your channel, and I actually find your content enjoyable. Mind-blowing. If you can teach this level of math to this lazy sixteen-year-old who's currently failing his Algebra II class, you can do anything, man.
I was once a high schooler who never had math explained in an interesting way, it was always do these 50 multiplication problems, i found math classes so boring. But schools are for stupid people, and later in life i learned the true beauty and importance of mathematics. The problem is I’m really interested in it but I suck at actually doing it. But as long as I don’t have to sit there trying to calculate stuff, a book about the Riemann Hypothesis is very interesting! That said, I’m so sorry you’re in high school. Unless you or your parents are already billionaires, you’re fucked :( You can’t imagine what the continued collapse of Western Civilization will mean, and what kind of life you’ll have - look at South Africa it’s exactly what the US will be like very soon, some parts already are. Life is one big intelligence test, and there are a lot of trick questions with counterintuitive answers. Wisdom is knowing what things are counterintuitive. Unfortunately today likes and followers trumps wisdom. Here’s a little simple math you should always keep in mind. The average person is a moron. This means, by definition, that 50% of people are dumber than morons. Never forget that, and if you’re with the majority on some opinion (not a fact like if "the sun rises in the east" but an opinion about, say, a movie or person) then you’re probably wrong. I’m talking about the fact vs opinion dichotomy in defamation law (because IAAL so it’s just an obvious distinction). Most people also would rather be happy and wrong (right now) than correct and unhappy (right now). Being correct and unhappy right now is always necessary for something to be successful in the future (work, time, sacrifice) - correct decisions if successful. Anyway, I just feel really bad for kids today. So glad I never had any, I could not handle having kids in this world, knowing the lives ahead of them. Weak men create hard times Hard times create strong men Strong men create good times Good times create weak men… and repeat. Take a guess where we are in this perpetual cycle. We don’t even have men anymore in the West, testosterone levels and sperm counts are at all time lows due to all the poisons in everything which nobody cares about because they are distracted by CO2 which is irrelevant. Do you know the % of CO2 in the atmosphere and how much it’s risen the past century? Look it up. 30 year old males are like 12 year olds. A 12 year old boy from 1850 could survive on his own and use a gun. I’m almost 50 and I didn’t feel like an adult until 40 or so. And our males are cutting their dicks off to become "women" real fast! Meanwhile the average woman today weighs more than the average man did in 1960. The hard times you’re going to face just make me so sad. Once, in another life, I was a lazy 16 year old taking high school math classes. I got to grow up in the 80s and 90s, a world free from racism and sexism, homophobia definitely existed though, but once it became acceptable to be out of the closet and everyone came out of the closet, everyone realized they knew plenty of good normal people who were gay, and homophobia went away in one generation, within my lifetime. Everyone generally cared about each other, everyone agreed an abortion was a bad, unfortunate thing even if they thought it should be allowed (“safe, legal, and rare” was the argument, with which I still agree). You’re being taught in your "school" that men and women are exactly the same, you can choose to be either gender, or any gender I should say, you can even make up your own. Don’t worry about algebra - do you know the difference between a male and a female? Because that’s way more important than math, and math is really fucking important. All of it, imaginary numbers are actually important. But no sense in being ok at math if everything else you know is wrong. Learn how to critically read a scientific paper. That’s probably the single most important skill in the world right now. Anyway, sucks to be you, sucks to be me, too. Unless you are a billionaire, in which case never mind.
@kaltkalt2083 Hi , I hope you are fine. I am a 36 years old failed Engineer in life who is trying to stand up strongly at age 40 from the scratch. I found your comment very interesting which is including advises to a 16 years old teeneger about the new era of life. Sorry for my English, because since it is my third language. I decided to discuss your comment with Chat GPT and got interesting result. Please find the result in below: "The fact that the commenter critiques the present in a pessimistic manner while idealizing the past can be explained by a psychological phenomenon known as "retrospective idealization" or "nostalgic idealization." In this type of thinking, people tend to overlook or minimize the problems of the past, while perceiving current issues as more significant and threatening. This way of thinking is particularly common as people age. Nostalgic idealization leads individuals to remember their youth or earlier periods as more positive, and the societal norms and life conditions of that time as better. They may downplay or dismiss significant issues like racism, sexism, or economic inequality that were present in the past, while viewing contemporary changes (such as gender identity discussions, technological advancements, or social media) more critically. This pattern of thought, especially in certain age groups, could be related to a midlife crisis. Individuals experiencing a midlife crisis often find themselves facing greater uncertainty in the middle years of their life and may begin to worry about the future. As a result, they are more likely to see the past as simpler and more manageable, while the current world appears more complicated and harder to control. This can lead to a perspective that is critical of the present but overly positive about the past. In addition, resistance to cultural or social change might also be part of the unease. A person might struggle to adjust to rapid social shifts and may feel more connected to the value systems of the past. This resistance can heighten anxiety about social structures changing and lead to a more pessimistic outlook on the future of society. In summary, the individual’s pessimistic view of the present and idealization of the past can be attributed to phenomena such as midlife crisis, nostalgia, and resistance to social change. These tendencies reflect difficulties in accepting or making sense of the cultural and social transformations they are experiencing. --- To help overcome this mindset, it would be beneficial for the individual to adopt a more balanced perspective. First, they should acknowledge that every era, including the past, had its own significant challenges and that today's issues are simply different in nature. Embracing social changes, staying informed about the positive advancements of modern society, and practicing mindfulness or gratitude for the present can help shift their outlook. Developing a mindset of adaptability and openness to change will also ease the transition and reduce anxiety about the future."
i dropped outta highschool at 12th grade, wish i didn't haha, i find myself actually retaining information with these videos though, like when the slit thing came up, i immediately thought about the double slit experiment i also like to watch these videos on a light trip, some of those visualizations (maybe inadvertently) are accurate to the visuals i get on a heavier trip, i can't imagine how hard it is to plug all that into MAnim.
As a Physics teacher who has derived the diffraction equation many times on a whiteboard with all the limitations of that medium, being able to direct my students to this video for a far far more robust visualization is incredible! Thanks as always Grant!
@@ekatvakushvaha1814 hope you watched it the animations were otherworldly, and I don't think they were hand rolled, I think they were simulations which is just so much more impressive.
I have been watching 3Blue1Brown for a long time. While most videos are brilliant, this one strikes me as outstanding. I may not know just how many other great channels there are, but of the few hundreds I know of, this is one of the absolute best. This is much more than edutainment, it feels like being handed a tiny but powerful and logical grip on the world - which in our arguably complex and chaotic times is a hard and commendable feat which I deeply respect and appreciate because it manages to calm and motivate. Which is to say: thank you! Thank you for this fantastic video.
@@3blue1brown I second what the OP said. I just want to add that you constantly say "you might be curious why that's the case" or "you might be left unsatisfied with that answer" or something along those lines when in reality most of us have never even seen such complicated ideas, let alone explain them deeply. I greatly, greatly appreciate it, but it's easy to take your work for granted (pun semi-intended) while watching these videos, because you take concepts that are almost always unexplored and not talked about and make us interested in learning more and more about them! Edit: also what @krishnachoubey8648 said, the optics series is superb, especially for a physics student like me!
@@3blue1brownim really not good at math, but these videos have fired me up, nowndays I've deluded myself to thinking im good at math and now i like the subject alot now. who knows maybe it'll be more than just an delusion
I learned, while I was still a teenager, that holograms store phase-information additionally to amplitude, on a film-plate. What always bothered me, was that no source ever explained why that would somehow lead to a recording of the full 3D scene, or how that scene would later be reconstructed. I always thought, that for that to work, the film somehow had to store the 'direction' of light beams. This Video was the first full explanation of how holograms are created, reconstructed, and why they do what they do, and it was beautiful. After more then 20 years of wondering if I would ever be able to undestand, what's going on in a hologram, you absolutely made my day!
This is something I've always wanted to understand, and already at 12:00 minutes in I have a much better understanding of this phenomenon than ever before. Also, Grant, your animations were already excellent like 5 years ago, but these are on an entirely new level. I'm so excited for the rest of this video!
Likewise! I gave a card to one of your apropos videos when I mentioned the Fresnel zone plate. Your videos remain, hands down, the best on optics RUclips has to offer.
This is by far the best explanation of holography. I'm amazed at how counter intuitive holography is in general and how complex even the basic principals turn out to be. I had no idea that somehow overlapping interference patterns could store this much information, let alone offer a way to just 'look at it' and somehow our eyes can perceive a recreated a 3d scene. Not to mention the surprising fact that film grain contains enough density for this to even be possible from an info theory standpoint, it's like you're somehow getting hundreds of exposures stored on a single exposure all via some interference wizardry.
I am so happy that you've decided to cover this topic. Has never quite clicked with me and I knew that I've been waiting for someone to really decode it in an easy to explain way
This genuinely feels like the joy of discovery I had all throughout my graduate Diffraction and Interferometry course, in just 45 minutes and with minimal prior grounding. It's astounding. Well done, truly, your videos never fail to be an amazing font of educational material and beauty in math and physics.
I have been curious about this process since highschool but couldn't really grasp it even with videos explaining it, so I am glad you are covering this topic without complicating everything with terminology. Thanks! More of this type of content please. Well. Not holograms specifically, but y'know.
I didn't imagine you would do an episode on holograms! Not only that, but you found the two exact holograms and features to be the most mindboggling as I did: any sort of glassware or lens in a scene, and a hologram of a microscope! Seeing these concepts explained with your animations is super helpful, especially the phase aspect. I would see it mentioned in explanations but wasn't sure how it was involved and I felt the interference argument alone was sufficient to understanding. The explanation about diffraction gratings and the various orders of light beams that they produced, answering how each affect things and why the others don't occur was excellent! I was thinking "but what about the other beams??" You're right about the complex number argument being "unsatisfying" on its own. But as an addendum to everything that preceded it in this video, it's a great cherry on top for completeness! The fact that the 2D plane containing the object wave in space _also_ projects that information out in 3D space doesn't seem as bizarre. That intuition doesn't make me feel certain that it's definitely the case (even though it is), but it also doesn't make me completely baffled as to why it is. Even though the reason why that is is a lot more complex. It feels like there's not much else it _could_ do besides travel out through 3D space in the same manner that the light reflecting off the scene originally did. But it feels like that intuition is still missing a lot more which is probably why that part would be a lot more complicated! Also, microfilm I see used resolves around 800 lp/mm (Fuji HR-21 or ADOX CMS 20) and they're kind of fun to use for regular photography because then you can quite realistically get 200MP+ from 35mm film. On the upper end of its resolving power you can get a gigapixel or more, that's why there was this one film developed called "gigabitfilm". 100-200lp/mm is well within the range of almost all professional films, color, black and white, slides or negatives. This video was totally awesome! Even since I saw that "Introduction to Holography" educational film you included and it showed how recording into the depth of the film had significance, that optics in a scene still "work", that you scan store multiple "channels", etc made holograms seemed like pure magic! That's why your video was so perfect to me!
thank you so much Grant and team for making this nobel prize discovery to be so digestible for the average physics enthusiasts. Seriously, from the bottom of my heart, thank you so much for the work you do.
Nothing else captures the joy of learning cool stuff as great as Grant does it. Feels like you get the payoff for days of studying into a single hour, eliminating any frustration you'd have encountered. 3b1b is truly the most amazing educator out there.
I can't fathom the amount of effort that must have gone into making this video. The animations were incredible, as was your approach to gradual enlightenment from first principles. We don't deserve you, but I'm really thankful you're here doing what you do.
How could you increase the quality of your work all the time. This video was like a snapshot of a whole optics curriculum which I could never felt the grasp until now. You are really putting in a brilliant use of computers. Wonderful work.
You seem to have this amazing knack for finding stuff I kind of thought I knew about already and exploring an entire additional layer of fascinating depth for it. Loving these sciencey themed videos!
I really like this style of explaining almost every concept necessary, but making it easy to skip over a part if your familiar with the concept beforehand. Really good video!
Grant, I know you love a good "Aha!" moment. For me in this video, it was around the 10:30 mark. Suddenly, the broad strokes of holograms suddenly made sense. Because of course! If you record the ways that two things interfere, and then send only one of those things through the interference, you're going to get the other! Excellent video, as always.
Dude that final message about re-discovering it for ourselves hit so hard - I promise that I will live my life in that way forever now! I love you so much man, you are so absolutely perfect when describing your videos! KEEP! IT! UP!
I accually wrote my bachelor thesis half a year ago about optimising computer generated holograms for digital hologram displays. I was looking for an intuitive explanation for holograms in general and didn't find it. until right now. Also I know how difficult it is to explain this topic and you did an excelent job.
In the video Grant describes his strategy: 11:50 "Universal problem solving tip number one is to begin analyzing any hard problem by taking the simplest version of that problem." Grant finds the most simplified case that still features the phenomenon of interest, and from there he builds step by step. The other part of course is: the visualizations. At any point where a narrator would find himself forced to say: "Now imagine that..." there is an animation.
I can’t help but truly appreciate the twist and turns and the brilliant moments of insights in this video. The more I kept watching this, the more I watch this the more I appreciate the complexity and artistry woven into the explanations. This is truly brilliant storytelling. Bravo
You just opened everyone's eyes to the beauty of the world around them. The kind of thing that reading a Richard Feynman book does, but with way less time & effort. I always wanted someone to explain these concepts properly in a video for a long time. ❤
This video is a phenomenal piece of art. Just imagine if your university teaches you in this way. Three to four years of production will result in the highest quality of educational content for a certain topic which could be used for years, and a lot of students will dive very deep into science out of extreme interest.
I've only just started watching but this sort of thing is what makes me want more development of light field cameras. The idea of being able to take a full 3D image of a scene is amazing, especially when you add on the ability to manipulate and explore that space digitally.
I have made several attempts to get a 10,000 ft understanding of this before and failed. I had to pause your video ten minutes in when it suddenly clicked - i paused again later when i realised the film itself acts as a diffraction grating, Many thanks - i now have enough understanding to be able to explain it in vague terms to someone else.
this has to be the most in-depth, well explained (with only small gaps due to my own lack of knowledge about optics), and BEAUTIFULLY animated video about the topic of holograms in general. this could easily be a 6 hour video and id watch it thoroughly to every detail.
Every time I watch a new 3B1B video, I am blown away by how much the production quality has improved! Loving the new animations especially with the light simulation! From khan academy to now, its amazing watching you perfect your craft. I don't think I'll ever get tired of watching your videos!
Over a decade ago I spent most of a year trying to wrap my head around this as I started my PhD focused on a certain type of optics and holography. Oh how I wish I'd had an explainer like this then! Thanks for reminding me of all this fun ❤
20:46 I’ve had so many questions about diffraction over my years of EE coursework and later optical projects. This one moment and graphic just made everything click. Thanks 3B1B
I compiled all knowledge for decades on a daily basis and followed the path here. If you do what you did in other videos and your associates did, you are dangerously close to being declared one of the smartest people ever.
I always get lost at the topology stuff, but for some reason, this is the easiest thing I ever learnt... in fact, his wording of the setup in the start was enough for me to be able to imagine how the hologram works
I am commenting on this video just in hope that it would increase the interaction of the video and help it get pushed to more people. Truly a genius and masterpiece.
The first hologram I saw, I was 11 years old at Expo 67 in Montreal. A chessboard scene. It was magic to me. Now I have the rudiments of an understanding of it. Thanks 3Blue1Brown!
Ever since your Linear Algebra series brought me through, well, Linear Algebra I’m a huge fan of your channel. This video is among your very best. Keep up the good work, you’ve done thousands of physics students a huge favor 🙏🙏🙏
The moment i realized that, i just shook my head saying "Fourier... of course it works that way", although i never before imagined the slits could be modified like that, to not be just two states.
@@mastershooter64 A sine wave has one and only one frequency. A Square wave has a fundamental frequency and many harmonics. Infinitely many harmonics if the wave is "square enough". 🙂
As someone who always loved math classes, this is a very welcome refresh of some things we did. I love the way this explanation is structured and actually goes down to some mathematics of this. I think my teacher would enjoy this
I have always wondered how those where made! A few mins in and I already had a mental image of the "shadow pattern" on the film that would capture that 3d data. Excellent video. Thus why it's there when you remove the actual objects. That combined EM field would only look like it does at the film when all the stuff is there with the reference wave. Wow.
3b1b videos make me feel a kind of smart I don’t get anywhere else. I may be, to an extent, spoonfed the information and how that information applies, but discoveries aren’t made shovel fulls at a time! You truly did give me that magic of rediscovering this idea, I feel like I need to go explain this to a dozen people
I was gonna watch a movie but then saw this. This is like a epiphany. It gives you an eye opening perspective of how light works. Literally mind blown !
To anyone that saw The Thought Emporium's recent video on diffraction gratings, notice that the holographic exposure pattern for the theoretical single point hologram is just like the grating he used to focus light using only diffraction.
I really, really love that time and time again, you explain the most complicated things really in depth, only to then give a 3 sentence short version of what you just explained. It really is the best of both worlds! I can at least try and watch the complicated parts 4-5 times the best to my ability until I get them, but the short concise explanation helps me get there faster when it comes to the more complicated and in depth version of the same topic! ❤
26:09 if u were wondering x/L should be tanθ, u r right, but x/L is very small here (we equating it to wavelength, that small) almost tending to zero, and if tanθ tends to zero, it is equal to θ itself and luckily that is also true for sinθ....so that's why, sinθ.....
amazing visualizations. Our physics teacher arranged a special holography recording event back in elementary school where we had a whole room full of kids sitting absolutely still while the exposure was happening. I marveled at the result but only after watching your video do I think I begin to understand the principles behind it. Thank you!
35:00 to 35:45 makes me envious to the point of anger. He captures a fundamental driving philosophy of mathematics and why I love the fundamental and abstract maths so much in a way I've not ever been able to describe. And he does it as an ASIDE, a lemma stepping stool with which to jump right back into his real lesson!
You know, I hate dealing with absolute bars (aka |Amplitude|) only because I never understood why we would need them even when someone sat down and explained it to me. Seeing the visual with the Amplitude of the wave at 6:20 made it make so much sense now!!! We don't want the negative of the sign wave, we always want to calculate the positive of the sign wave, but because we don't always have positive numbers, those bars flip the output giving us the positive (aka the top of the sign wave) that we desire. Man no matter what it is you make, you always help me understand in ways no teacher could! Thank you so much :D
I read about these principles in a book about 25 years ago. Lets see.. oh yes it was called Mind At Light Speed by a scientist named David Nolte. It was fun. Needless to say, your presentation is much better than any book.
Appreciate the vid. Went into physics with a grant to study optics but ultimately left the department over the horrible political struggles to just exist in upper level academia 😢. Swapped disciplines but always wanted do delve back into it on a deeper level. Keep it up bro!
This is so heartwarming for me. My big brother died 10 years ago and i still got a set of hologram films he made for his master of science. I never really understood what he wanted to explain to me when he showed me those. (Like also referencing holographic principles related to the encoded informations stored on blackhole surfaces or something? 😅) The films are some scenes but also a digitally generated cube which spins at a faster angle then you look at. Like you can look at it from all sides even when you only shift your angle of view or the laser pointer by less than 180°. I always was so fascinated. I wondered how so much 3D information can be encoded on 2D. I am so thankful to now understand it more ❤❤❤
~30:40 It's like the beam's order being the resulting frequency bumps of a fourier transform. Sine-like gradient slits can produce only the 1st order (the 0th being always the equivalent of DC 0hz on fourier). Square-like slits produce more orders, as their shaping is composed by many "sine-like gradient slits stacked"
Omg the Taylor Swift reference at 3:25 ... "Your hologram stumbled into my apartment, hands in the hair of somebody in darkness named Chloe or Sam or Sophia or Marcus"
Mind blown! Thank you! What I find ultra facinating here, that we get to jump a dimention: We get a 3D image from a 2D source, and we don't break physics! The next "step" would be to pull the 4th dimention from 3D objects. Imagine having some technique / device that views the Klein bottle in 4D... I remember in the early '90's a hologramic video game, but that is not the same as this. As an electronics engineer (with the focus on the engineer part), I found this ultra-facinating. Additionally, I work for a company that produces telescopes (mounted in satellites to observe earth). Although I'm not directly involved in optics, it is good to know some of the theories.
That's amazing! When you flip the film, you actually view the whole scene from the perspective of the objects in the scene! Holographs are amazing. I only now got a glimpse of the meaning of the imaginary part of complex numbers. I wish we had these kinds of explanations when I was at school...
7:42 it might not be clear for most people why recording the phase of the light wave is relevant to record a 3d image on a 2d plane, but, being a physicist I will give a shot before watching the rest of the video. A point in a 3d object reflects light in all directions, so the light from that single point will essentialy hit all points of the film, but the distance between that point and the ones in the film will be different, therefore the time they will be hit is different, therefore the phase of the light that will initially hit each place will also be different. If you can record said phase you will have a vague record of the distance between each point of the film and the target point. If this effect is applied to every point in the 3D object, the sum of all the information may indeed create the ilusion of looking through a window. This would honestly be best explained with an animation (if I am even correct). I hope this is what the video has in store!
The reason you capture 3D is because of the depth - the 3rd dimension - of the object scene. A single point is not 3D, since it has no depth. As explained in the video, a single point gives a "phase footprint" of a Fresnel zone plate. If you moved the the single point away from the film, you'd get a different zone plate. Now, if you had two single points separated by some distance, you'd get two zone plates superimposed on the film, each slightly different from each other. The two zone plates represent the distance between the two points and transfer information of the relative distance of the two points. If you had a "cloud" of points in space, you'd get multiple zone plates, which would transfer information about the relative placement of the points in the cloud. If you had an infinite number of points, say each point on a porcelain cat, every point (on the cat) would create a separate zone plate, and you'd have a mess, as seen when he magnifies the interference structure. But, that mess is an encoding of all the distances between every point on the cat - a 3D scene.
and if you expand the idea of holography you can even draw connections between a black hole and our universe, but the deeper connections definitely go beyond my current knowledge
This is the best explanation of holograms that I have ever seen, and the only one that has made intuitive sense. I especially like the explanation of how 3D information can be stored on 2D film. Bravo!
I loved this video - as always, the explanations were really clear and the video was made beautifully. I did have a question though: at 26:11, isn't x/L equal to tan(theta'), not sin(theta')?
You're right, silly me! It's all an approximation anyway, since the grating is not evenly spaced (the spacing gets smaller farther away), so the diffraction equation wouldn't hold exactly either. This does make me wonder if a tighter analysis accounting for that non-uniform spacing would result in something closer to tan(theta) in the diffraction equation. In either case, all the more reason to lean on the more formal explanation to fill in the gaps.
@@3blue1brown No, it's sin(theta_nought). Tan(theta_nought) is the inclination of the beam to the axis - the tilt of the beam relative to the axis. If the point source were far enough away, the beam would be collimated and tan(theta) would be constant across the plate. However, the lines of equi-phase up, or along, the plate is given by the grating equation, lambda = d*sin(theta_nought). If the beam were tilted at theta_nought, then, assuming that the x axis were up the plate, and z is perpendicular to the plate, the distance between wavefronts of the laser at an angle theta_nought, relative to z, are related to the lines of constant phase along the x axis ("up the plate") by d = lambda/sin(theta_nought). Imagine lines spaced at equal distances along your ray which is tilted at theta_nought to the z axis, and perpendicular to your (tilted) ray direction; this is the wavelength, lambda. If you now project the distance between two of the wavefront lines onto the x axis, the distance between the lines on the x axis - d - is given by d = lambda/sin(theta_nought). By the way, I've been a holographer since 1981, working on display holography and technical holography (Holographic Optical Elements). This is one of the best, clearest explanation I've seen for some time. I've known Craig and Sally for many years. If you run into them, say Dinesh says hello. I also graduated in Theoretical Physics from the University of London, and have been following your maths and physics videos which I find are very clear and informative. I especially liked the course on Special Relativity.
This video is utterly amazing. It is mindblowing. It is amazing how fourie transforms materialize in the exposures on the film. It is amazing how math actually materialize in physical form.
Spoiler: Most of the things people call "holograms" have ABSOLUTELY NOTHING to do with holography. A 2D image you can see through like the spinning LED fans, the famous Tupac performance (see "Pepper's ghost") etc. simply are not holograms. Of course pretty much every media source calls them holograms because they can't let accuracy get in the way of a cool headline.
I love how he shows a hologram of R2D2 projecting a sci-fi “hologram” before saying it’s possible to make a hologram of a computer-generated scene, so for a moment it kinda sorta looks like sci-fi holograms are possible too.
This video was such a joy to make. Thanks again to Craig Newswanger and Sally Weber for showing us the ropes.
Two mathematical corrections:
1) In the analysis at 26:10, we should do a Taylor approximation about d=0, not about x=0. If you this right, the result at the bottom will look like x / sqrt(L^2 + x^2), which conveniently cancels out another (much sillier) mistake, which is how x / L in this case is not sin(theta'), but tan(theta'). Thanks to those who spotted that, I guess I must have been happy enough to see the desired sin(theta') at the end that I didn't properly double check how we got there.
2) In the end, I referenced treating |R^2| as "some real number", so that it's only scaling O. This only makes sense to do because the amplitude of R is constant. Or at least, it varies only very slowly around a point. In this way, what I say a few moments later about making no assumptions about R is not quite right, we do need to assume it's a wave with relatively constant magnitude across the film.
I was always told that any part of a hologram contains all of the information in the hologram as a whole. This gave me such a better understanding of what that actually meant and how it isn’t entirely true (in the way that I was thinking about it). Thank you for these amazing videos!!
It's genuinely one of your best videos (imo). It was a delight to watch.
26:31 A potentially more elegant way to reason through this is:
the two distances shown in 14:58 have to be destructive at each black point. this happens when D and the distance of that other line to its right. The way of finding these distances and angles between the two lines functions THE SAME WAY we did in the section “Diffraction gratings”, so we end up with the same formula. @3blue1brown
26:31 A potentially more elegant way to reason through this is:
the two distances shown in 14:58 have to be destructive at each black point. this happens when D and the distance of that other line to its right. The way of finding these distances and angles between the two lines functions THE SAME WAY we did in the section “Diffraction gratings”, so we end up with the same formula. @3blue1brown (I wrote it twice to get your attention.)
I didn’t do any formal analysis to justify this, but: the image you see when you flip over the film to look at the conjugate image doesn’t look like a weird distorted version of the original to me - I think it looks like what you would see if you were inside the original scene looking out?
17:06: "Let's take a side-step into a mini-lesson so I don't have to rob you of that joy."
lol, I love it! Never change, Grant!
I totally lost interest and stopped watching the video during that side step.
@@HankMeyer skill issue
@@HankMeyer You should remember all the times a teacher or tutorial just skipped over a step you wanted to know more about and understand
Grant doesn't do that and it is a very nice thing on this channel - he gives you the full picture
If you want to skip over you still can - so yeah. Skill issue
Without question, the best video on how a hologram works that I have seen in my 42 years of making holograms. What’s more, I made one of the three holograms shown at the beginning of the video in the living room of my first house in 1986-87.
Wait, that's amazing, which one?
@@3blue1brown The hologram portrait 'Lucy in a Tin Hat' was shot by Royal College of Art holography student Patrick Boyd and I whilst at the RCA in the mid-1980s (the first Master of Arts holography course in the world). As one of the three founding members of staff of the RCA's holography Unit, I designed, built, and operated the RCA's pulsed laser hologram portrait studio, but operated my own private holography studio at my home at the same time. I would often take the student's master holograms home to shoot the reflection hologram copies at my studio during the night for maximum brightness, as the stability in my living room was far better than at the Royal College! Stephen Benton, inventor of the rainbow hologram, often told me that it was the best hologram portrait he had ever seen. The Microscope was of course by Dutch holographer Walter Spierings. I particularly liked your use of a single-point Fresnel zone plate, followed by multiple points and thus overlaid zone plates to explain complex holograms. I use this method myself but have not seen it in a video before. The visualizations and graphics are incredible. Again, well done.
@@3blue1brown Lucy in a Tin Hat
hell yeah buddy!
@@3blue1brownHey check out my new beautiful equation. X²*X²*X²*...♾️ < X³ this is a simplified version... Think about it, a square is two-dimensional meaning length and width only with absolutely no depth... A cube function has depth... If it has depth then that means infinite amounts of two-dimensional existence can stack into any size three dimensional existence... Thus this equation is fundamental. Yet another mathematical shattering of the status quo. ² means squared ³ means cubed... This solves so many problems with math and creates a lot more maybe.
At 11:40 I genuinely was so surprised by what I was seeing. I had no idea this was even possible. It literally looks like you’re looking through a portal to another world. Light is so cool!
This is the most beautiful hologram class I ever have. 30 years ago, I produced my first hologram in the optics lab of the university. It was a real magic, but to this artwork, I only catched very fuzzy realizations from the vector equations in my textbook. That was an era without internet and youtube video. Thank 3b1b, guys that helps production this video, and the astonishing IT technology, to give me such a deep and visualized unstanding on hologram!
Just as an addendum about the astonishing IT technology behind Grant's videos: it's actually all programmed and mathematically correct. He writes hundreds of lines of Python code for all his videos. He wrote his own library and improves it for his needs.
As a rare hologram (REAL ones) nerd, this might be my favorite video on RUclips of all time. Your simulations are always so beautiful, and getting to see those museum pieces was incredible
11:39 This feels like it would make an incredible element in an escape room. Have a table set up, and to solve the puzzle you need to find these chips with different scenes recorded on them at the same table
Already implemented in a video game called The Room
@@synthersentezci😊
@@synthersentezciYou’re tearing me apart, Lisa
This would be incredibly cool, but I fear that these disks would likely get lost easily, get damaged or possibly stolen too. And judging by the delicacy of the process, it's likely not cheap either.
So yes, amazing idea, but most likely impractical.
@@MechMK1 maybe sandwich them between tampered glass?
I'm a high schooler who couldn't attain a tenth of your mathematical knowledge if I tried, but I still frequently find myself returning to your channel. It's not something you can exactly verbalize, but it's clear that you're an accomplished educator who can take complex and out-there ideas and ground them in basic logic and understanding. I'm frequently blown away by a channel my dad watches. I need to stress that - my dad watches your channel, and I actually find your content enjoyable. Mind-blowing. If you can teach this level of math to this lazy sixteen-year-old who's currently failing his Algebra II class, you can do anything, man.
I was once a high schooler who never had math explained in an interesting way, it was always do these 50 multiplication problems, i found math classes so boring. But schools are for stupid people, and later in life i learned the true beauty and importance of mathematics. The problem is I’m really interested in it but I suck at actually doing it. But as long as I don’t have to sit there trying to calculate stuff, a book about the Riemann Hypothesis is very interesting!
That said, I’m so sorry you’re in high school. Unless you or your parents are already billionaires, you’re fucked :( You can’t imagine what the continued collapse of Western Civilization will mean, and what kind of life you’ll have - look at South Africa it’s exactly what the US will be like very soon, some parts already are. Life is one big intelligence test, and there are a lot of trick questions with counterintuitive answers. Wisdom is knowing what things are counterintuitive. Unfortunately today likes and followers trumps wisdom.
Here’s a little simple math you should always keep in mind. The average person is a moron. This means, by definition, that 50% of people are dumber than morons. Never forget that, and if you’re with the majority on some opinion (not a fact like if "the sun rises in the east" but an opinion about, say, a movie or person) then you’re probably wrong. I’m talking about the fact vs opinion dichotomy in defamation law (because IAAL so it’s just an obvious distinction). Most people also would rather be happy and wrong (right now) than correct and unhappy (right now). Being correct and unhappy right now is always necessary for something to be successful in the future (work, time, sacrifice) - correct decisions if successful. Anyway, I just feel really bad for kids today. So glad I never had any, I could not handle having kids in this world, knowing the lives ahead of them.
Weak men create hard times
Hard times create strong men
Strong men create good times
Good times create weak men… and repeat.
Take a guess where we are in this perpetual cycle.
We don’t even have men anymore in the West, testosterone levels and sperm counts are at all time lows due to all the poisons in everything which nobody cares about because they are distracted by CO2 which is irrelevant. Do you know the % of CO2 in the atmosphere and how much it’s risen the past century? Look it up. 30 year old males are like 12 year olds. A 12 year old boy from 1850 could survive on his own and use a gun. I’m almost 50 and I didn’t feel like an adult until 40 or so. And our males are cutting their dicks off to become "women" real fast! Meanwhile the average woman today weighs more than the average man did in 1960. The hard times you’re going to face just make me so sad. Once, in another life, I was a lazy 16 year old taking high school math classes. I got to grow up in the 80s and 90s, a world free from racism and sexism, homophobia definitely existed though, but once it became acceptable to be out of the closet and everyone came out of the closet, everyone realized they knew plenty of good normal people who were gay, and homophobia went away in one generation, within my lifetime. Everyone generally cared about each other, everyone agreed an abortion was a bad, unfortunate thing even if they thought it should be allowed (“safe, legal, and rare” was the argument, with which I still agree). You’re being taught in your "school" that men and women are exactly the same, you can choose to be either gender, or any gender I should say, you can even make up your own. Don’t worry about algebra - do you know the difference between a male and a female? Because that’s way more important than math, and math is really fucking important. All of it, imaginary numbers are actually important. But no sense in being ok at math if everything else you know is wrong.
Learn how to critically read a scientific paper. That’s probably the single most important skill in the world right now.
Anyway, sucks to be you, sucks to be me, too. Unless you are a billionaire, in which case never mind.
@kaltkalt2083 Hi , I hope you are fine. I am a 36 years old failed Engineer in life who is trying to stand up strongly at age 40 from the scratch. I found your comment very interesting which is including advises to a 16 years old teeneger about the new era of life. Sorry for my English, because since it is my third language. I decided to discuss your comment with Chat GPT and got interesting result. Please find the result in below:
"The fact that the commenter critiques the present in a pessimistic manner while idealizing the past can be explained by a psychological phenomenon known as "retrospective idealization" or "nostalgic idealization." In this type of thinking, people tend to overlook or minimize the problems of the past, while perceiving current issues as more significant and threatening. This way of thinking is particularly common as people age.
Nostalgic idealization leads individuals to remember their youth or earlier periods as more positive, and the societal norms and life conditions of that time as better. They may downplay or dismiss significant issues like racism, sexism, or economic inequality that were present in the past, while viewing contemporary changes (such as gender identity discussions, technological advancements, or social media) more critically.
This pattern of thought, especially in certain age groups, could be related to a midlife crisis. Individuals experiencing a midlife crisis often find themselves facing greater uncertainty in the middle years of their life and may begin to worry about the future. As a result, they are more likely to see the past as simpler and more manageable, while the current world appears more complicated and harder to control. This can lead to a perspective that is critical of the present but overly positive about the past.
In addition, resistance to cultural or social change might also be part of the unease. A person might struggle to adjust to rapid social shifts and may feel more connected to the value systems of the past. This resistance can heighten anxiety about social structures changing and lead to a more pessimistic outlook on the future of society.
In summary, the individual’s pessimistic view of the present and idealization of the past can be attributed to phenomena such as midlife crisis, nostalgia, and resistance to social change. These tendencies reflect difficulties in accepting or making sense of the cultural and social transformations they are experiencing.
---
To help overcome this mindset, it would be beneficial for the individual to adopt a more balanced perspective. First, they should acknowledge that every era, including the past, had its own significant challenges and that today's issues are simply different in nature. Embracing social changes, staying informed about the positive advancements of modern society, and practicing mindfulness or gratitude for the present can help shift their outlook. Developing a mindset of adaptability and openness to change will also ease the transition and reduce anxiety about the future."
i dropped outta highschool at 12th grade, wish i didn't haha, i find myself actually retaining information with these videos though, like when the slit thing came up, i immediately thought about the double slit experiment
i also like to watch these videos on a light trip, some of those visualizations (maybe inadvertently) are accurate to the visuals i get on a heavier trip, i can't imagine how hard it is to plug all that into MAnim.
@@oka-yoke This is exactly why I don’t use AI, it always gives a California democrat response to everything. Don’t trust it.
3B1B is actually the best educational channel on RUclips
maths and science is better
Why is it that guided discovery isn't used as a teaching method in schools? It seems much more effective.
@@adammontgomery7980 simple: to keep people dumb and programmed, no gov wants smart or self aware people.
@@adammontgomery7980 more effort. Teachers aren't paid enough for this
@@adammontgomery7980 the school system is unfortunately outdated by about 200 years, that's one of the reasons
As a Physics teacher who has derived the diffraction equation many times on a whiteboard with all the limitations of that medium, being able to direct my students to this video for a far far more robust visualization is incredible! Thanks as always Grant!
Still can't help but being blown away by the quality in these videos...
bro watched the entire video in 3 minutes
@@ThatShushi17-mc7ct Jokes on you, I didn't watch at all💀
@@ekatvakushvaha1814 hope you watched it the animations were otherworldly, and I don't think they were hand rolled, I think they were simulations which is just so much more impressive.
I have been watching 3Blue1Brown for a long time. While most videos are brilliant, this one strikes me as outstanding. I may not know just how many other great channels there are, but of the few hundreds I know of, this is one of the absolute best. This is much more than edutainment, it feels like being handed a tiny but powerful and logical grip on the world - which in our arguably complex and chaotic times is a hard and commendable feat which I deeply respect and appreciate because it manages to calm and motivate. Which is to say: thank you! Thank you for this fantastic video.
High praise, thank you. This particular video was such a joy to make, I'm glad it resonated.
@@3blue1brown Sir I'm blown away. Please continue this series on optics. It has been a joy to learn from you. 💖💖
@@3blue1brown I second what the OP said. I just want to add that you constantly say "you might be curious why that's the case" or "you might be left unsatisfied with that answer" or something along those lines when in reality most of us have never even seen such complicated ideas, let alone explain them deeply. I greatly, greatly appreciate it, but it's easy to take your work for granted (pun semi-intended) while watching these videos, because you take concepts that are almost always unexplored and not talked about and make us interested in learning more and more about them!
Edit: also what @krishnachoubey8648 said, the optics series is superb, especially for a physics student like me!
@@3blue1brownim really not good at math, but these videos have fired me up, nowndays I've deluded myself to thinking im good at math and now i like the subject alot now. who knows maybe it'll be more than just an delusion
@@nabibbs2402Watch every single khan academy video on basic maths. That's how I started my journey. Now I'm a math undergrad student 😊
Fresh 3 blue 1 brown video to savour on a Saturday, dosent get much better
Truee
I agree
Monday dude yea Sunday since 19 hrs passed
I learned, while I was still a teenager, that holograms store phase-information additionally to amplitude, on a film-plate. What always bothered me, was that no source ever explained why that would somehow lead to a recording of the full 3D scene, or how that scene would later be reconstructed. I always thought, that for that to work, the film somehow had to store the 'direction' of light beams. This Video was the first full explanation of how holograms are created, reconstructed, and why they do what they do, and it was beautiful. After more then 20 years of wondering if I would ever be able to undestand, what's going on in a hologram, you absolutely made my day!
This is something I've always wanted to understand, and already at 12:00 minutes in I have a much better understanding of this phenomenon than ever before. Also, Grant, your animations were already excellent like 5 years ago, but these are on an entirely new level. I'm so excited for the rest of this video!
Great work Grant, your explanations and animations are truly next level!
❤
such is yours, too
Jeroen - I was hoping you'd hop in and see this. I love seeing your work, and explanations, as well.
Likewise! I gave a card to one of your apropos videos when I mentioned the Fresnel zone plate. Your videos remain, hands down, the best on optics RUclips has to offer.
@@3blue1brown With an endorsement like that I gotta go check them out I guess.
3Blue1Brown just called me "rather clever" and this unironically made my entire day.
Great experience wasn't it :) I got there (and ohhhh'd) just as he was saying that
This is by far the best explanation of holography. I'm amazed at how counter intuitive holography is in general and how complex even the basic principals turn out to be. I had no idea that somehow overlapping interference patterns could store this much information, let alone offer a way to just 'look at it' and somehow our eyes can perceive a recreated a 3d scene. Not to mention the surprising fact that film grain contains enough density for this to even be possible from an info theory standpoint, it's like you're somehow getting hundreds of exposures stored on a single exposure all via some interference wizardry.
Yup, the magic of interference and Fourier transforms, I love it!
I am so happy that you've decided to cover this topic. Has never quite clicked with me and I knew that I've been waiting for someone to really decode it in an easy to explain way
This genuinely feels like the joy of discovery I had all throughout my graduate Diffraction and Interferometry course, in just 45 minutes and with minimal prior grounding. It's astounding. Well done, truly, your videos never fail to be an amazing font of educational material and beauty in math and physics.
I have been curious about this process since highschool but couldn't really grasp it even with videos explaining it, so I am glad you are covering this topic without complicating everything with terminology. Thanks! More of this type of content please. Well. Not holograms specifically, but y'know.
"The universe can often be elegantly and beautifully modelled by mathematics"
42:32 RRRRRORROROO
Scooby Doo was actually trying to teach us about holograms.
I didn't imagine you would do an episode on holograms! Not only that, but you found the two exact holograms and features to be the most mindboggling as I did: any sort of glassware or lens in a scene, and a hologram of a microscope!
Seeing these concepts explained with your animations is super helpful, especially the phase aspect. I would see it mentioned in explanations but wasn't sure how it was involved and I felt the interference argument alone was sufficient to understanding.
The explanation about diffraction gratings and the various orders of light beams that they produced, answering how each affect things and why the others don't occur was excellent! I was thinking "but what about the other beams??"
You're right about the complex number argument being "unsatisfying" on its own. But as an addendum to everything that preceded it in this video, it's a great cherry on top for completeness! The fact that the 2D plane containing the object wave in space _also_ projects that information out in 3D space doesn't seem as bizarre. That intuition doesn't make me feel certain that it's definitely the case (even though it is), but it also doesn't make me completely baffled as to why it is. Even though the reason why that is is a lot more complex.
It feels like there's not much else it _could_ do besides travel out through 3D space in the same manner that the light reflecting off the scene originally did. But it feels like that intuition is still missing a lot more which is probably why that part would be a lot more complicated!
Also, microfilm I see used resolves around 800 lp/mm (Fuji HR-21 or ADOX CMS 20) and they're kind of fun to use for regular photography because then you can quite realistically get 200MP+ from 35mm film. On the upper end of its resolving power you can get a gigapixel or more, that's why there was this one film developed called "gigabitfilm". 100-200lp/mm is well within the range of almost all professional films, color, black and white, slides or negatives.
This video was totally awesome! Even since I saw that "Introduction to Holography" educational film you included and it showed how recording into the depth of the film had significance, that optics in a scene still "work", that you scan store multiple "channels", etc made holograms seemed like pure magic! That's why your video was so perfect to me!
thank you so much Grant and team for making this nobel prize discovery to be so digestible for the average physics enthusiasts. Seriously, from the bottom of my heart, thank you so much for the work you do.
I refreshed youtube and was like wtf 2 seconds ago ! Always a pleasure seeing one of your vids pop up on my feed!
Nothing else captures the joy of learning cool stuff as great as Grant does it. Feels like you get the payoff for days of studying into a single hour, eliminating any frustration you'd have encountered. 3b1b is truly the most amazing educator out there.
a 45 min 3b1b video?!! I don't know what good deed I
did to deserve this.
I can't fathom the amount of effort that must have gone into making this video. The animations were incredible, as was your approach to gradual enlightenment from first principles. We don't deserve you, but I'm really thankful you're here doing what you do.
How could you increase the quality of your work all the time. This video was like a snapshot of a whole optics curriculum which I could never felt the grasp until now. You are really putting in a brilliant use of computers. Wonderful work.
You seem to have this amazing knack for finding stuff I kind of thought I knew about already and exploring an entire additional layer of fascinating depth for it. Loving these sciencey themed videos!
I swear you may never know when or where these information are useful but when they are in a class it feels the best thank you for all of your videos
I really like this style of explaining almost every concept necessary, but making it easy to skip over a part if your familiar with the concept beforehand. Really good video!
Grant, I know you love a good "Aha!" moment. For me in this video, it was around the 10:30 mark. Suddenly, the broad strokes of holograms suddenly made sense. Because of course! If you record the ways that two things interfere, and then send only one of those things through the interference, you're going to get the other! Excellent video, as always.
Dude that final message about re-discovering it for ourselves hit so hard - I promise that I will live my life in that way forever now! I love you so much man, you are so absolutely perfect when describing your videos! KEEP! IT! UP!
I accually wrote my bachelor thesis half a year ago about optimising computer generated holograms for digital hologram displays.
I was looking for an intuitive explanation for holograms in general and didn't find it. until right now.
Also I know how difficult it is to explain this topic and you did an excelent job.
Do you have access to that thesis still? Currently working though an optics course and would love to see how you've approached things.
In the video Grant describes his strategy: 11:50 "Universal problem solving tip number one is to begin analyzing any hard problem by taking the simplest version of that problem." Grant finds the most simplified case that still features the phenomenon of interest, and from there he builds step by step.
The other part of course is: the visualizations. At any point where a narrator would find himself forced to say: "Now imagine that..." there is an animation.
@@WeAreChecking I do, but I don't know if it is what you need and don't know how to send it to you.
I can’t help but truly appreciate the twist and turns and the brilliant moments of insights in this video. The more I kept watching this, the more I watch this the more I appreciate the complexity and artistry woven into the explanations.
This is truly brilliant storytelling.
Bravo
When the world needed him the most...he turned up!
You just opened everyone's eyes to the beauty of the world around them. The kind of thing that reading a Richard Feynman book does, but with way less time & effort. I always wanted someone to explain these concepts properly in a video for a long time. ❤
Words are not enough to express how much I adore this channel.
This video is a phenomenal piece of art. Just imagine if your university teaches you in this way. Three to four years of production will result in the highest quality of educational content for a certain topic which could be used for years, and a lot of students will dive very deep into science out of extreme interest.
The quality of the animations and the explanations in this video are just mind-blowing. Especially 20:24 is so mesmerizing.
I've only just started watching but this sort of thing is what makes me want more development of light field cameras.
The idea of being able to take a full 3D image of a scene is amazing, especially when you add on the ability to manipulate and explore that space digitally.
I have made several attempts to get a 10,000 ft understanding of this before and failed. I had to pause your video ten minutes in when it suddenly clicked - i paused again later when i realised the film itself acts as a diffraction grating, Many thanks - i now have enough understanding to be able to explain it in vague terms to someone else.
this has to be the most in-depth, well explained (with only small gaps due to my own lack of knowledge about optics), and BEAUTIFULLY animated video about the topic of holograms in general. this could easily be a 6 hour video and id watch it thoroughly to every detail.
3B1B you have single handedly reignited my love for math and knowledge in general. Thank you.
Every time I watch a new 3B1B video, I am blown away by how much the production quality has improved! Loving the new animations especially with the light simulation! From khan academy to now, its amazing watching you perfect your craft. I don't think I'll ever get tired of watching your videos!
Amazing video! As someone who works in holography in the lab, this explanation helped me a lot!
Over a decade ago I spent most of a year trying to wrap my head around this as I started my PhD focused on a certain type of optics and holography. Oh how I wish I'd had an explainer like this then! Thanks for reminding me of all this fun ❤
It can’t get better than this for a great start for the weekend. Thank you Sir.
20:46 I’ve had so many questions about diffraction over my years of EE coursework and later optical projects. This one moment and graphic just made everything click. Thanks 3B1B
Probably my favourite video of yours so far. So incredibly well explained at such a good pace!
I compiled all knowledge for decades on a daily basis and followed the path here. If you do what you did in other videos and your associates did, you are dangerously close to being declared one of the smartest people ever.
I always get lost at the topology stuff, but for some reason, this is the easiest thing I ever learnt... in fact, his wording of the setup in the start was enough for me to be able to imagine how the hologram works
I am commenting on this video just in hope that it would increase the interaction of the video and help it get pushed to more people. Truly a genius and masterpiece.
The first hologram I saw, I was 11 years old at Expo 67 in Montreal. A chessboard scene. It was magic to me. Now I have the rudiments of an understanding of it. Thanks 3Blue1Brown!
Ever since your Linear Algebra series brought me through, well, Linear Algebra I’m a huge fan of your channel. This video is among your very best. Keep up the good work, you’ve done thousands of physics students a huge favor 🙏🙏🙏
30:37 My first thought was harmonics. Like a radio wave that is a sine does not create harmonics, but a square wave does.
The moment i realized that, i just shook my head saying "Fourier... of course it works that way", although i never before imagined the slits could be modified like that, to not be just two states.
what do you mean sine waves don't create harmonics?
@@mastershooter64 A sine wave has one and only one frequency. A Square wave has a fundamental frequency and many harmonics. Infinitely many harmonics if the wave is "square enough". 🙂
The elegance of nature makes me so serene... The last sentence gave me shivers.
As someone who always loved math classes, this is a very welcome refresh of some things we did. I love the way this explanation is structured and actually goes down to some mathematics of this. I think my teacher would enjoy this
I have always wondered how those where made! A few mins in and I already had a mental image of the "shadow pattern" on the film that would capture that 3d data. Excellent video. Thus why it's there when you remove the actual objects. That combined EM field would only look like it does at the film when all the stuff is there with the reference wave. Wow.
3b1b videos make me feel a kind of smart I don’t get anywhere else. I may be, to an extent, spoonfed the information and how that information applies, but discoveries aren’t made shovel fulls at a time!
You truly did give me that magic of rediscovering this idea, I feel like I need to go explain this to a dozen people
The best video to coherently explain the magics of hologram I believe ever!
I like what you did there.
I was gonna watch a movie but then saw this. This is like a epiphany. It gives you an eye opening perspective of how light works. Literally mind blown !
To anyone that saw The Thought Emporium's recent video on diffraction gratings, notice that the holographic exposure pattern for the theoretical single point hologram is just like the grating he used to focus light using only diffraction.
wow... i have to say, these videos very often blow my mind (at least a little), but this one... absolutely incredible. indescribable. thank you, Grant
This was crazy good, super insightful, extremely well-made, and spaced in a followable clearly structured way!! Thanks! ❤
I really, really love that time and time again, you explain the most complicated things really in depth, only to then give a 3 sentence short version of what you just explained.
It really is the best of both worlds!
I can at least try and watch the complicated parts 4-5 times the best to my ability until I get them, but the short concise explanation helps me get there faster when it comes to the more complicated and in depth version of the same topic!
❤
26:09 if u were wondering x/L should be tanθ, u r right, but x/L is very small here (we equating it to wavelength, that small) almost tending to zero, and if tanθ tends to zero, it is equal to θ itself and luckily that is also true for sinθ....so that's why, sinθ.....
Only 10 minutes into the video and I already feel like this is the best video I’ve seen on your channel. Truly magnificent🎉
i first thought its another video from sebastian lague about his 3d renderer. holograms are a neat idea to implement.
amazing visualizations. Our physics teacher arranged a special holography recording event back in elementary school where we had a whole room full of kids sitting absolutely still while the exposure was happening. I marveled at the result but only after watching your video do I think I begin to understand the principles behind it. Thank you!
35:00 to 35:45 makes me envious to the point of anger. He captures a fundamental driving philosophy of mathematics and why I love the fundamental and abstract maths so much in a way I've not ever been able to describe. And he does it as an ASIDE, a lemma stepping stool with which to jump right back into his real lesson!
You know, I hate dealing with absolute bars (aka |Amplitude|) only because I never understood why we would need them even when someone sat down and explained it to me. Seeing the visual with the Amplitude of the wave at 6:20 made it make so much sense now!!! We don't want the negative of the sign wave, we always want to calculate the positive of the sign wave, but because we don't always have positive numbers, those bars flip the output giving us the positive (aka the top of the sign wave) that we desire.
Man no matter what it is you make, you always help me understand in ways no teacher could! Thank you so much :D
I read about these principles in a book about 25 years ago. Lets see.. oh yes it was called Mind At Light Speed by a scientist named David Nolte. It was fun. Needless to say, your presentation is much better than any book.
Your recent videos have really been hitting it out of the park, wow. Truly fantastic. I keep thinking that they're the best video you've ever made
I've seen that type of microscope hologram in person, I can tell you that it is very trippy.
Each of your videos is not only educational, it is emotionally moving.
Thank you
Appreciate the vid. Went into physics with a grant to study optics but ultimately left the department over the horrible political struggles to just exist in upper level academia 😢. Swapped disciplines but always wanted do delve back into it on a deeper level.
Keep it up bro!
This is so heartwarming for me. My big brother died 10 years ago and i still got a set of hologram films he made for his master of science. I never really understood what he wanted to explain to me when he showed me those. (Like also referencing holographic principles related to the encoded informations stored on blackhole surfaces or something? 😅) The films are some scenes but also a digitally generated cube which spins at a faster angle then you look at. Like you can look at it from all sides even when you only shift your angle of view or the laser pointer by less than 180°. I always was so fascinated. I wondered how so much 3D information can be encoded on 2D. I am so thankful to now understand it more ❤❤❤
~30:40 It's like the beam's order being the resulting frequency bumps of a fourier transform. Sine-like gradient slits can produce only the 1st order (the 0th being always the equivalent of DC 0hz on fourier). Square-like slits produce more orders, as their shaping is composed by many "sine-like gradient slits stacked"
This was my immediate intuition! But "patterns fool ya", so that intuition is hardly good reasoning.
I really can't thank you enough for producing such high-quality videos and giving them us practically for free!
Omg the Taylor Swift reference at 3:25 ... "Your hologram stumbled into my apartment, hands in the hair of somebody in darkness named Chloe or Sam or Sophia or Marcus"
I loved that! it's the perfect video topic for this swiftie easteregg :)
Mind blown! Thank you!
What I find ultra facinating here, that we get to jump a dimention: We get a 3D image from a 2D source, and we don't break physics! The next "step" would be to pull the 4th dimention from 3D objects. Imagine having some technique / device that views the Klein bottle in 4D...
I remember in the early '90's a hologramic video game, but that is not the same as this. As an electronics engineer (with the focus on the engineer part), I found this ultra-facinating. Additionally, I work for a company that produces telescopes (mounted in satellites to observe earth). Although I'm not directly involved in optics, it is good to know some of the theories.
the conclusion is just wow❤
That's amazing! When you flip the film, you actually view the whole scene from the perspective of the objects in the scene!
Holographs are amazing.
I only now got a glimpse of the meaning of the imaginary part of complex numbers. I wish we had these kinds of explanations when I was at school...
please continue the serie of probability
and the machine learning serie
series*
@@fullfungo wow...i really suck at english
Many videos of 3B1B actually blew my mind, but this one takes it one step further.
7:42 it might not be clear for most people why recording the phase of the light wave is relevant to record a 3d image on a 2d plane, but, being a physicist I will give a shot before watching the rest of the video.
A point in a 3d object reflects light in all directions, so the light from that single point will essentialy hit all points of the film, but the distance between that point and the ones in the film will be different, therefore the time they will be hit is different, therefore the phase of the light that will initially hit each place will also be different. If you can record said phase you will have a vague record of the distance between each point of the film and the target point. If this effect is applied to every point in the 3D object, the sum of all the information may indeed create the ilusion of looking through a window. This would honestly be best explained with an animation (if I am even correct). I hope this is what the video has in store!
The reason you capture 3D is because of the depth - the 3rd dimension - of the object scene. A single point is not 3D, since it has no depth. As explained in the video, a single point gives a "phase footprint" of a Fresnel zone plate. If you moved the the single point away from the film, you'd get a different zone plate. Now, if you had two single points separated by some distance, you'd get two zone plates superimposed on the film, each slightly different from each other. The two zone plates represent the distance between the two points and transfer information of the relative distance of the two points. If you had a "cloud" of points in space, you'd get multiple zone plates, which would transfer information about the relative placement of the points in the cloud. If you had an infinite number of points, say each point on a porcelain cat, every point (on the cat) would create a separate zone plate, and you'd have a mess, as seen when he magnifies the interference structure. But, that mess is an encoding of all the distances between every point on the cat - a 3D scene.
Whatching tour videos after having tried your video library is something that i'll never recover from
and if you expand the idea of holography you can even draw connections between a black hole and our universe, but the deeper connections definitely go beyond my current knowledge
This is the best explanation of holograms that I have ever seen, and the only one that has made intuitive sense. I especially like the explanation of how 3D information can be stored on 2D film. Bravo!
I loved this video - as always, the explanations were really clear and the video was made beautifully. I did have a question though: at 26:11, isn't x/L equal to tan(theta'), not sin(theta')?
You're right, silly me! It's all an approximation anyway, since the grating is not evenly spaced (the spacing gets smaller farther away), so the diffraction equation wouldn't hold exactly either. This does make me wonder if a tighter analysis accounting for that non-uniform spacing would result in something closer to tan(theta) in the diffraction equation.
In either case, all the more reason to lean on the more formal explanation to fill in the gaps.
@@3blue1brown No, it's sin(theta_nought). Tan(theta_nought) is the inclination of the beam to the axis - the tilt of the beam relative to the axis. If the point source were far enough away, the beam would be collimated and tan(theta) would be constant across the plate. However, the lines of equi-phase up, or along, the plate is given by the grating equation, lambda = d*sin(theta_nought). If the beam were tilted at theta_nought, then, assuming that the x axis were up the plate, and z is perpendicular to the plate, the distance between wavefronts of the laser at an angle theta_nought, relative to z, are related to the lines of constant phase along the x axis ("up the plate") by d = lambda/sin(theta_nought).
Imagine lines spaced at equal distances along your ray which is tilted at theta_nought to the z axis, and perpendicular to your (tilted) ray direction; this is the wavelength, lambda. If you now project the distance between two of the wavefront lines onto the x axis, the distance between the lines on the x axis - d - is given by d = lambda/sin(theta_nought).
By the way, I've been a holographer since 1981, working on display holography and technical holography (Holographic Optical Elements). This is one of the best, clearest explanation I've seen for some time. I've known Craig and Sally for many years. If you run into them, say Dinesh says hello.
I also graduated in Theoretical Physics from the University of London, and have been following your maths and physics videos which I find are very clear and informative. I especially liked the course on Special Relativity.
Grant, you can take all the time you want between videos if you’re going to produce and give us this kind of production. Incredible piece. Thanks man.
I'm sorry but that's the coolest damn thing I've ever seen
Many years ago, i took a half-semester's course on almost exactly what was covered in this video, and this 45 minute video did a better job.
31:00 That looks a lot like a Fourier transform of square wave vs sine wave
Spot on! You got it!
so true!
Immediately jumped to the comments to point this out as well
This video is utterly amazing. It is mindblowing. It is amazing how fourie transforms materialize in the exposures on the film. It is amazing how math actually materialize in physical form.
Please explain other types of holograms in some follow-up videos!
We beg you!
Spoiler: Most of the things people call "holograms" have ABSOLUTELY NOTHING to do with holography. A 2D image you can see through like the spinning LED fans, the famous Tupac performance (see "Pepper's ghost") etc. simply are not holograms. Of course pretty much every media source calls them holograms because they can't let accuracy get in the way of a cool headline.
@@StubbyPhillips I know, but another types of real holograms explained would be great!
I've been making holograms for over a year now, and i still needed to see this. Thank you!
T.I.L: Holograms are real.
I love how he shows a hologram of R2D2 projecting a sci-fi “hologram” before saying it’s possible to make a hologram of a computer-generated scene, so for a moment it kinda sorta looks like sci-fi holograms are possible too.