I've always wondered about optical computing as well. Thanks very much for your video on the topic. Some ideas: I was recently reading about electrical memristors. Perhaps you could use photochromic materials as an optical memristor. I'm not sure if this would add an additional complexity or perhaps you could use photochromics without diffraction patterns to make a logic gate. Maybe also use polarization along the lines of "spintronics"? Looking forward to more!
Thanks for the suggestion Ben. If would be really nice if such a material could be sputtered or thermally evaporated as a thin layer on the evaluator side of the device. Because photochromics could introduce the non-linearity in the gate to make it behave in a more binary manner. Anyway, I'm not sure what is feasible for me to make. Looking into a concept is easy, but to make an actual optical processor would take many months of hard work...
I too am interested in optical computing, though I don't have all the fancy gear yet to start working on any sort of prototype but the ideas are there. If either of you 2 ( Applied Science/Huygens Optics wants to chat on some of them I am more then open for it as I would hate to see the ideas go to waste. Besides this project is probably much bigger than what a single person could do anyway.
I've had this idea floating in my head for a while as well but had no idea how it would be executed. The optical lock idea is great and I loved the LPL reference.
@@NicholasMarshall I am sure they could be encased in something to protect them, maybe a clear see-through resin for example. ( hopefully which wouldn't cause further issues reading the key )
This would need to be electronic no doubt. Just had an idea that is more robust. Why not use a usb key containg an ssh key? Should be impossible to "pick" or guess. If the software and hardware implementation is sound, it should be amazing!
@@Thor110 A resin could protect them from shattering but would reduce the number of 'pins' you could have (no matter how clear the resin is, it's going to diffract some light requiring more spacing and/or larger 'pins' to compensate). Resin could still potentially scratch as well which would make it useless. That said the key could be incased in something a bit more solid with some foam to absorb shock, the 'pins' could be inset inside the 'tip' of the key (hope that makes sense) with a simple mechanical shutter that opens when the key is inserted so the 'pins' are only exposed when the key is being used (kind of like a how floppy disk or VHS expose their disk/tape when inserted). One or more of the 'pins' could act like inputs into the key which could actually make the keyhole a part of the key as well (not sure if that would be useful in any way), more importantly the source of light should come from the keyhole with the key being solid state. Obviously like any e-lock the keyhole would need to have a backup power supply and preferably a way to provide power should it's main and backup power supplies fail though I could see that being a potential weak point depending on implementation (need to not only prevent rewiring but also make sure it can't be broken by undervolting or overvolting it).
Nice presentation. Many current optical logic gates desings are based on the 'inteference' principle, for example those based on MZI. Phase delays are usually tuned by changing refractive index of materials or the length of light path. The diffractive method may have some advantages in computation (not necessarily logic gates since interference gives more than that). You may be interested in the following two papers:1.All-optical machine learning using diffractive deep neural networks and 2.Deep learning with coherent nanophotonic circuits. These two looks quite different, however both are based on interference.
That demonstration sweeping through the focal plane just blew my mind. I had no idea you could so precisely control the angle and phase of light with a 2D pattern. The ability to use lithography makes this very scalable and repeatable. I can see a lot of possibilities in stacking layers.
I am on my to a PhD on coherent combination of fiber channels and I was thinking about using the device for optical computation. Well keep you posted 😉
@@bertnorticus1662 Computing is not out of the question but let's say that the PhD got me well. You can see the lastest development of the laser by searching for the XCAN laser!
I've always had cursory knowledge about the specifics of how electronics work, especially in computing... I'm more of an artist. Although it helps when thinking outside of the box. The idea of photons instead of electrons has always intrigued me and has led me on a quest of understanding computing on a deeper level. Seeing you work on this is truly inspiring to see! Keep going!
Just wanted to say, that analogue programming is an emerging field for machine learning. I am FAR from an expert, but I am sure that some data science firms would be happy to talk to you :p
This concept was part of my graduate work in the mid-1990's. A journal article in Applied Optics was published entitled, "Programmable optical logic systems using free-space optical interconnections."
Thank you sooooo much! I played with this effect about two years ago (used hair instead of those tiny patterns) and was totally amazed by how you can focus the light without a lense. The resources online are not too great on this topic so your video was a bliss for me :D
Absolutely fascinating. I'd love to see more about this, especially if it's possible to "chain" multiple of these gates in series. For instance, It'd be great to see a basic adder constructed in this way.
Super impressed! A couple of things come to mind: 1) the multi-lobed outputs 12:36 reminded me of QAM (Quadrature Amplitude Modulation) lobes. 2) the diagram in the lower right corner at 4:03 reminded me of the averaging functions of artificial logic processors. I think you're onto something brilliant! Good Luck!
It's been my long interest in trying to understand the concept of OPTICAL SIGNAL PROCESSING, which you speak and explain so marvelously. The ability to construct and implement it in real world-physical fabrication and use, sets my highest respect for your knowledge and tenacity to construct when others, white paper simulate. You are the bomb. The days of AT&T's Bell Lab research in optical / photonic / light wave for which journals I marveled, generated all this time asking and waiting ... "why is it taking so long to replace electronics". I now struggle in taking my unscientific knowledge, but having tremendous desire to proactively offset the financial pain from the rising cost and future decreased availability of secured energy- and design its practical use. ..You present the realism for someone like myself to attempt and implement its use for the common good. Thank You
Absolutely brilliant! I love the intersection of ideas from theoretical physics and having the knowledge and equipment to conduct practical experiments. Great job on the video production both the content and visualizations are excellent! Channels like this one truly make me believe that we are in a gold age of citizen science. Keep up the great work!
This is incredible. I'm familiar with digital logic, but these types of optics are beyond my level of education. I've always wondered how optical computing would work.
0:32 Wow, just the other day i gave this explanation to my mom, but soon after i realized that the light can't cancel into nothing. I can't believe i haven't thought of that before. I didn't take the time to look up a better explanation though, so catching it here is pretty nice.
Congratulations on your work, I'm an engineer and I always imagined we'd have optical logic ports someday. Now I see that Chinese are already developing optical computers. I really enjoyed your work congratulations. That's the future
This is really cool. You need to find a way to get rid of any frequency / phase shifts introduced by the "light logic gate" itself, this is the holy grail. Because then you can build bigger blocks without the need for massive error correction.
For that it would probably be nescessary to use patterns with sub-wavelength dimension. However, it is not all bad. There are also ways to use these phase shifts to your advantage....
To build something like a computer you have to be able to put gates in series. Use the output form one gate as the input to another without going through an detector and diode laser.
This is such a fascinating concept. I have imagined optical computers based on hexagonal crystals with the optical operators on the hexagonal faces and the data on the end faces with the output data being through an optic fibre cable for conversion to standard electronic function elsewhere. There are so many fabulous mechanisms such as using air (vacuum) gaps to allow past data to jump ahead of current data, optically clear piezo electric crystals to deflect beam direction, and photonics devices are beginning to appear. The prospect is to build fast computers that are immune to EMPs, but also have indefinite life to store the history of our civilization beyond its inevitable collapse. Keep going, this is huge.
I concur, EMP is a huge issue, if the world would know that all the electronics of an entire country can be broken in a few seconds with EMP, they would never use silicon chips
I know what I will do when I studied physics (another life) and am in my pension. The same thing you do, this is super interesting, I'm glad I subbed, you're brilliant IMHO
so cool! when i heard about all the strange non-linear optical effects certain materials had I got straight to thinking how they could be used to build gates. w/ Raman amplification and cross-phase modulation, you can basically build all-optical transistors. optical phase conjugation just blows my mind.
I believe there is a crystal that change opacity to a certain wavelenght when lit with another wavelength. I think it was in an experiment about stoping light. If you have 2 crystal that behave in opposite way, first one is clear to booster wavelength when activated by signal wavelength, the booster wavelength allows signal light to be set clear, which keep the first crystal clear... It could then be latched off with destructive interferance. I might not be clear, but it might still help
As he points out, state based switches for read/write memory are way more important than the computation. It's all arbitrary unless you can, how did you put it, flippity-flopp.
Yeah I was thinking about how to do some sort of latching. Idk, maybe latch data between 2 mirrors in a laser with a way to optically turn off and on the laser. That way data could be latched in, and continuously pumped with the laser medium. No idea how that would be done. I suppose to design a data flow engine, latching is not required. Analog data flow engines with op amps don't seem to require latching data (things just flow in one side and results come out the other). In order to run software I would imagine you would need some way to latch bits or chunks of analog streams. I would have to turn on my brain to think about the minimum requirements to run software which I'm not prepared to do rn. Sounds like work.
I think the crux of the problem is that with only superpositions, I don't see how it would be possible to implement anything like a mux or flip flop. If you could use intense light to make pits in glass like a rewritable CD, and if you can boost the light's signal, then I think it could probably be done, but it would be quite slow compared to any normal computer, and I don't know how many times glass like that can change phase.
Woooow this is actually something I have been working on for many years! It is interesting seeing someone using interference! I had only considered using it for developing a not gate, my work has mainly been around taking advantage of optical filters and defraction to reflect and change colours of lights in order to produce gates. I have always thought taking advantage of light for its colour properties would be the way, but what you have here is far more impressive! Would love to see more!
I think "why i make a basic calculator worked by colors" and you appeared before me... its unbelievable think mate its very cool. And homemade CPU, its fantastic!!
Very nice work. I had a related idea a while back to "compute" by convolution at the Fournier plane. You might find some happy rabbit holes to go down with this method. Basically compute the fwd FFT of the logic you wish to impart, and then etch that as a mask.
Only recently discovered this channel (thanks to the double slit experiment video), just finished watching everything you have here. Liked it very much! Maybe i'll go sort through my tiny box of salvaged optics now...
He presented a very interesting parallel processing architecture towards the end. A matrix of inputs exists on one side. The inputs would be loaded from a memory cache. The inputs go through a matrix of generators and evaluators. The output is read by an optical sensor. The memory cache is updated from the values read by the optical sensor. This process repeats in cycles. There would need to something that reads and writes to the memory cache. In this way a program can be loaded and evaluated, and the results read. This is a very cool concept! The process is not too dissimilar from a frame buffer on computer graphics. Frames of data could be preprepared ahead of optical processing. The frames get added to a processing queue that gets processed FIFO by the optical processor.
Interesting idea. I’m imagining a glass cubed cpu with optical fiber inputs and outputs. I think we will be using light for general computing sometime in my lifetime. It’s getting too expensive to make the latest processors using semiconductors.
I remember a family friend who worked at Lucent telling me that they were working on a fiberoptic network switch that would direct the flow of traffic without media conversion. No copper. I wasn't able to tease an explanation out of him (that I could understand, dunno why was telling a kid my age something like that anyway) and I've wondered about it once or twice a year ever since. I think I've finally got an answer to that question that I understand, thanks.
Oh my! You, Sir took me back in 1995 when I have envisioned a similar approach! I have a Word document in an old hard drive somewhere! If I find it I will send it to you!
You should try to create an optical transistor, where the input doesn't come from the other sources but a third that controls them. And maybe a two sided device that makes the light go back and forth.
add sensors at both destructive and constructive points to give a ratio output, use log amps to help digitize, allows more precision over a much larger bandwidth of light level variations. etch the outer ring of interference filters on the other side of the glass to get back your genius win. make the thickness correct for height delta to re-align focal points in space. poppa was a photon magician, learned this stuff in the back seat of a station wagon. great videos. your tesla valves can be used to generate water level differences. This can be used to measure flow direction and pressure differentials with fluid induced optical path changes. This can be used as a logic device for flow control and measurement
this was recommended to me. Its incredible. Also i wanna see you partnering with some metal worker on yt to make that lock a reality to finally defeat LPL
Excellent. I've been wondering about using optical wave interference for making optical transistors for a long time (probably a million other people have invented it in their heads as well). I considered capturing the wave peaks and using that light in the next transistor, but thought you would perhaps need amplification to have enough photons. Goods that this idea is being shared as someone might gain me insight to actually building a optical computer one day.
If you could use left and right hand circular polarisation the system would become immune to phase shifting caused by thermal expansion which would be quite useful.
@@zyeborm I've always wondered if it would be possible to basically add or subtract 2 wavelengths from each other and use that for math within a processor (hope that makes sense). Not sure how to handle logic with such a system though (maybe use a specific set of wavelengths that have this sort of constructive/destructive behavior).
I've thought about optical logic using optical ring resonators a lot since I saw a presentation at a RISC-V conference a few years ago. Ring resonators seem to be pretty trivial quantum devices because their boundaries are easy to understand, leading to interesting yet comprehensible topologies. Anyway, every time you release a video, I hope that you talk about photon sieves again and lead into clever applications for computation. Thanks for the interesting video in the meantime!
Destructive interference places the light somewhere else. How important those words are. First year physics teaches that photons cancel each other out, or it did in my day. Thanks for saying it, even if I change around your exact quote.
@@razhemo4191 They don't need to be pickable: when locksmiths cannot open a door through low-effort means, they just drill the core out and replace the lock. If I put in a lock strong and secure enough that breaking down the whole door is the only way to get in, chances are that requiring this degree of effort was the whole point of putting in such a strong lock in the first place.
Realistically speaking, if going down the route of electronic locks, I think a fully enclosed RFID lock would be strictly better. Not as fun, for sure, but better.
@@chuuni6924 "better" only depends on how difficult it is to spoof the signal it wants to open.. An electro-optical logic gate lock would take a fantastical amount of effort to non-destructively open
@@SuperAWaC Cracking an AES key would also take a fantastical amount of effort. Certainly, there are more and less secure RFID protocols, but as long as you're doing electronic locks, I'd trust properly implemented cryptography over virtually anything else. Now, if you could find a way to implement this optical key in a manner that didn't require electronics, that'd be a different thing altogether...
@@chuuni6924 There is a video where they use a child's toy to hack the signals in garage door openers. I think it was Veritasium. It was pretty eye opening.
The idea of a adding a third always-on beam is ingenious. It's also absolutely necessary for creating a NOT, otherwise there would be no light for a "0" source. :)
I remember years ago pulling apart a cleverly engineered optical keyboard, it had a row of lights going down channels to led detectors at the other end. Each key had plate that would interrupt the light channels thus producing the ASCII character code for the key pressed. So you could implement a full optical computing system from input to logic and then work on optical output- wouldn’t that be cool.
The treason to build optical computers is for speed (single core or parallel processing). The optical to electron conversion is slow and bulky. We need photon switches that are mechanical/electron independent.
I was also come up with a very similar implementation for the optical logic circuits few years from now, it's very nice to see it practical implementation.
I wonder if there would be any benefit in trying to make zone plates with smoothly varying sinusoidal opacity, instead of the usual fully opaque and fully transparent stripes. I don't know how small you can get your details with your lithography setup, pretty small it seems, :) but perhaps you could use a sub-wavelength dither or sawtooth to transition between opaque stripes and transparent stripes. If I recall, moth's eyes do something similar to this, but in three dimensions. Their eye lenses don't have smooth glass-like surfaces, but rather the surfaces are blanketed with an array of sub-wavlength cones at sub-wavlength spacing, which the longer wavelength light treats as a gradual transition from the refractive index of air to the refractive index of the denser eye material. This gradual transition helps reduce the loss of light to specular reflection, making the moth's eyes more efficient. In the case of zone plates, you'd be creating a similar effect in the 2D zone pattern, by incorporating a sub-wavelength drop-off pattern in the opaque material as you transition out of opaque stripes into transparent stripes. If you could get the effective opacity to vary sinusoidally, then you'd have a zone plate that behaved much more like the pair of touching glass blocks you showed at 0:15, in terms of smoothly varying transmission and reflection stripes. This sinusoidal zone plate pattern might also help reduce the higher order additional focal points. Anyway, just a thought. Fantastic channel by the way. :)
Making gradual phase changes in the rings of zone plates can definitely improve optical performance. This is basically what is achieved in high-resolution meta surfaces.
TL;DR: Ordinary optical components are linear, and no combination of linear components can produce a non-linear device. XOR is non-linear. Optics is a wonderful field, and your craft and hand-on demonstrations are very beautiful, and a pleasure to watch. I certainly am not writing this to criticize you in any way, but merely to point out some fundamental considerations to be aware of. Ordinary optics (meaning a fixed arrangement of lenses, mirrors, diffraction gratings, filters etc) is *linear* in the sense that if an electromagnetic wave "A" at the input produces the output "X", and an input "B" produces the output "Y", then any mixture of A+B at the input produces a corresponding mixture of X+Y at the output. A Fourier transform is a linear operation, which satisfies the above property. Hence, it can be realized by an ordinary optical system. (Any other weighted sum or difference of inputs can also be realized.) But a lot of interesting computation is *not* linear or reversible. XOR is already very nonlinear! Threshold that is inherent in all of the ordinary electronic logic gates, even in inverters, is a non-linear transformation. Obviously, multiplication and division are non-linear, etc, etc. Finding roots of a quadratic equation is non-linear. Almost any computer program is extremely non-linear. In general, universal computation fundamentally cannot be realized with just the linear elements (the ordinary optical components.) To make a universal computer, one would have to add non-linear optical elements into the system. Such nonlinear optical elements do exist and are used occasionally to great effect (frequency doubling, for example, like in green laser pointers), but as of yet there is no easy to use, inexpensive non-linear optical element that would be equivalent to a transistor. With the ordinary linear optics, you can make a linear mixture of the inputs that resembles some logic operations. But without sneaking in some non-linear operation, no matter how you cascade these linear blocks, the result will always remain a linear system, and some even very simple things like XOR will not be even approximately realizable. There are of course great many other things that only optics can do. Good luck with your experiments -- love your work!
very few people they have the charisma to CREATE technology.... tesla it was one of them . if you have something like this i really wish you to succed .. you have my positive energy and my best wishes.
*@Huygens Optics* 12:41 What happens if you make this a spiral instead? Each revolution it goes 1 "band" (white to white) outwards. It changes thickness according to whatever the thickness you use at any radius here.
It seems to me that development of the refractive patterns would be helped along by an accurate computer simulation of the behviour of light waves and a genetic algorithm to spawn a multiplicity of potential patterns. A genetic algorithm would possibly get you to patterns that you would never have considered.
I'm currently working on running simulations for optical neural net components. Good to see more people are considering the potential in integrated photonics. I don't know if interference is the right strategy though considering the difficulty of getting interference on chip with enough nodes.
0:46 The explanation actually makes perfect sense. Destructive interference does not destroy the EM energy, but two waves of equal amplitude and opposite phase will not have an effect on the rods or cones in your eyes, or a light sensor in a camera. Both rays of light still reach their destination but cannot have an effect because of their evil twin.
I think you misunderstood there. The electric energy is not secretly there, but "undetectable" or "unabsorbable", the energy literally does not go there, but somewhere else. If you make glasses anti-reflective more light goes through. The light isn't "silently" reflected. I do not understand why it does that, but it is doing that. (Please correct me if I misrepresented your understanding of the topic, it's the educator in me talking)
@@CXT14GamerMouse 🤔 Hmm. So if two coherent laser beams of equal amplitude, and wavelength, but opposite phase were fired into my eyeball, they would pass right through my retina? Continuing ad infinitum into the sunset? Now I'm confused 😂 I just assumed they would both be absorbed but only as heat
@@Jeremy.Bearemy The light would not even go into your eye, the interference would make a pattern offset from your eyes. In your contraption the energy would again: go somewhere else. I don't have the skill to give an explanation which is not false in the context of a youtube comment, I would probably struggle if I had a whole week. I would love to teach you, but I think you are on the right track. Just keep me in mind the few next times you watch interesting videos about light and try to accept my premise. You will see how it fits, and how light is always weirder than you think. I wish you good luck and stay curious :)
I was working on this process and the application of this process as far back as more than 9 years ago, but less than 10 years ago. I was working on redundancies to allow for full application of this process in the form of hi speed primary memory and processing logic at least as far back as Fall of 2019. I had concepts for mitigating waste heat and recovering waste photons, etc. One of the immediate advantages of this process is that you can make an optically actuated clock, and with negligible difference in waste heat production, run a hypothetical cpu, or bus, or memory at several orders of magnitude faster switching/clock speeds than the viable ceiling in semiconductor processing(mitigating the problem of gates operating in the shorter end of the x-ray band having slightly longer delays than is applicable in the best viable semiconductor gates, and especially applicable if working with uv light - which is more immediately testable ). I had strategies for approaching the prototyping and testing of a drop in replacement for ram in sodimm form factor, but needed to wait until I had more resources for fabrication. Imagine a massive fpga array that occupies almost no space, has 1/1000 the latency of a conventional fpga array, and consumes 1/10 of a watt? It is hypothetically possible to create a switchable diffraction array in multiple physical planes of interaction that can be intermittently changed to affect diffraction of indefinitely many poly-degree layers of diffraction/interaction. In other words, there is a straightforward path to making a processor that can physically change it's architecture across extremely short timeframes.
Fibre-optic gyroscope use interference also. I do not know much, but maybee here are some good ideas, how to split and combine two beams. this topic is very fascinating. thanks for sharing.
As I'm sure you're aware, all logic gates can be built by series of XOR gates or XAND gates. So if you can produce a very simple and reliable XOR, you have everything you need to build arbitrary microprocessors!
WRONG! First of all, there's no such thing as "XAND", the opposite of XOR is XNOR. What exactly is an exclusive and gate in your mind and how is it different from an exclusive or gate? Think mcfly think! But the only thing you can make out of a series of XOR gates is..... more XOR gates, or XNOR gates. The term you are looking for is "turing complete", and the only 2 logic gates that are turing complete are NAND and NOR gates. To Cristian, to your comment, you can make flipflops out of nand or nor gates, by having a pair of them with their outputs led back to one of each others' inputs, and that gets you your memory, that's why you can't do it with xor gates, because it doesn't work to feed their outputs back to their inputs.
Great video! An un-picable lock. Brilliant. You should file for a patent on that if you are the first, or at least write a whitepaper and have it published - even on TH-cam if no one will pick it up. Optical computers, this is very stimulating (no pun intended). If you could do this with individual photons, quantum computing may merge with this. For those of you not familiar with digital logic gates: In electronics, all you really need is NAND gates because a 2nd NAND gate (with one input tied to a logic '1') on the output of the first acts as a NOT (inverter) gate and converts the NAND gate to an AND gate. So, using NAND gates, you can make: NAND, NOT, AND, OR, NOR, EXCUSIVE OR, EXCLUSIVE NOR, and any other gate with various combinations NOT on the inputs and output... and you have ALL the building blocks of computer logic. With Optical Logic, you start OR and NOT gates, and those too can be combined in various ways to create ALL of the same building blocks gates used in electronics. For example: Demorgan's Therom states you can convert, say an OR gate to an AND gate by putting a NOT on each input and output of the OR gate. Try it: The truth table of a Negitive Logic OR gate (one with NOT on the all the inputs and output) and truth table of an AND gate, both tables give the same results with respect to their inputs (thus the same gate, just inverted "logic/polarity" symbols). A postive logic AND gate is the same as a Negative logic OR gate, they do the same but you look at the logic from positive or negative perspectives, so the symbols are different but do effectively the same.
Interesting, I've been tooling around with the idea in my head for a while. Should be a good video. =) Edit: Ok finished the video. This is similar to what I was thinking. My idea was based upon the double slit experiment and you'd basically fire two beams of photons (one beam per slit) and if both were on, you'd get photons in the center of the diffraction pattern at the "aperture", so basically an AND gate. I hadn't really worked out the NOT gate yet but once that was figured out you could build a NAND gate and then from there since its a universal gate you could build any of the other logic functions; OR, XOR, etc.. and well... things just progress from there. Sure since everything is NAND the gate count goes up, but given the speed at which it would run, I don't think one would care until you're pushing the limits of the technology. One concern if chaining gates along to form logic and computational units is the attenuation of the light going from one gate to the next. Since the light is diffracting I would suspect some photonic loss at the aperture. So at some point you'd need a signal booster of some sort. This was one of those things where I figured if I had thought of it surely someone somewhere else much smarter than I had already thought it through and determined it wasn't viable and hence why we don't currently have the technology. =) But hey, maybe there's something to it after all? It's certainly interesting stuff.
Thanks, you have clearly given it a lot of thought. I myself thought that this type of configuration would be well documented by others. But what you see is that efforts are mainly directed to "in-plane" configurations, so that processing is more compatible with IC manufacturing. And you are right about the efficiency. With every diffractive element, you loose at least 50% of the light. But with a limited number of layers, I guess light intensity loss will not be a very big issue.
@@HuygensOptics That’s where I think that building an optical key sounds like a good idea. Electricity is just too good at running electronics since it is just so easy to use changes in magnetic fields to flip relays or charge up capacitors or quickly change the properties of P-doped transistors to allow other current to flow. What you basically need for a photonic circuit to be as good as an electrical one is to find some way to have light particles on one side of a transistor cause the other side of the transistor become transparent (and then become opaque when no light flows, or Vice versa) in order to avoid needing to revert back to electricity to control the flow of light
@@HuygensOptics To address the attenuation problem, I suppose you could pass the output of the logic gate through a laser cavity with the end mirrors removed (i.e. utilise the Light Amplification bit of the LASER acronym) - to get more amplification you could fold the beam through the cavity a few times. Perhaps a dye laser would be suited to this - obviously the laser would have to have the same wavelength as the amplifier. Possibly you could use a single cavity to amplify numerous beams. But I suppose if you have a long beam path you would end up with optical logic that is slower then current electronic logic.
@@johndoggett808 even if it were slower it would still have uses. A solid state computational device that's immune to electromagnetic interference would have many uses.
Hi! I love the idea of optical logical gates as well as logical computing using interference like this, and the demonstrations in this video are really quite wonderful to look at :) However, I think that this type of logic gate can not work in larger systems. The reason for that is that the way the light is combined is purely linear. This means that when switching multiple gates behind one another, the result is not a nice and clean 1 or 0, but rather some linear combination of the outputs - it always has to be an addition of the wave functions. An "OR" gate, for example, can not just output 0/1, but rather 0/1/2, and you would have to deal with the different phases of the output signal of the XOR/XNOR gate before feeding it into the next gate. Some sort of nonlinearity has to be used to break this linear combination and provide true logic gate functionality.
Diffusing Silica (glass) on other layers, you could make micro fiber optic paths to connect the gates together. And, if diffraction patterns could be introduced in these fiber/optic paths, they could combine at an aperture - that would eliminate need for the diffuser layer as this would be encoded into the paths themselves resolving into logic functions where they come together at various aperatures.
Ok. I’m using my 100micrometer shim to provide tension. Constructive interference on gate 2. Gate 3 feels like it’s in shadow. That’s a click from gate 4. Back to gate 1.
Very cool stuff. I think the real promise of this type of circuit is in power savings and parallelism (multiple wavelengths, each representing a different set of inputs, could potentially be run simultaneously through a single circuit). BUT, I'm not an optics expert.
Exactly my thought as well! Even though it has been shown to work in isolation doesn't mean it will be feasible to use in series. This could be applied to perform complex hard-coded calculations, so in a way it could shorten the instruction pipeline of a CPU -- though I don't think the conversion from electrical information to optical and back again will be faster than doing all of that using the same data source.
I think it might be significantly easier for you to use edge based diffraction gates so that you could lay out your work with more ease. The way that might work is by reducing your optical path from planer to a linear. You could use glass etching techniques to create fresnel lenses that are phase based, and with the optical paths that are through the edge of the plate, rather than normal to it. Furthermore, using phase based diffraction elements allow you to increase your optical power in the first order lobes of your pattern significantly since it won't be lost to the DC angular plane waves you have to deal with when using purely absorvative filters. Furthermore, reading bens comment about using photochromic materials to introduce nonlinearities/memory gave me the idea that you could selectively sputter these materials into wells created by glass etching, which would allow you to place pockets optically nonlinear material!
The problem is that light is (generally) linear. You could talk about these as individual gates, but if you actually connect them together, no matter what you do the final result will be a linear combination of what you started with. You can't get complex logic. Not unless you add something to make it nonlinear, like having a light sensor that triggers a laser. There are ways to do that, but I think that's the interesting part of the problem that needs to be focused on. Not something you can just ignore.
But they are faster and less limited than electronics, so you can get more milage from a similar arrangement. LED would be optimized for it's circuit. Because you couldn't directly link them all together, each circuit could have a differently tuned LED source, specific to it's purpose.
Very exciting work, having watched the earlier elements you presented I was left wondering where your mad genius was leading ;) Wishing you the best of luck and may the photons be kind to your research.
Whelp, if you've never heard of me I guess I'd better just wander on back into my hut. Not that it matters, I'm not really much of a donkey to hear of. 😶
very cool bro, wanted to make it like couple of years ago, but couldn't implement due to lack of access to optics and time, any way just wanted to tell you it is very cool that you are doing it
I remember designing something back in the 90s that required an LED to flash 10,000 times per second, and I ran into the problem that the LED would remain glowing for many microseconds after it was no longer powered. (Maybe LED technology has moved on.)
Awesome video, the concept and execution shows that this idea could be further developed (and maybe miniaturized). That would give a whole new meaning for optical devices
True but think about how much energy is in light at that scale compared to that of electricity in current machines. It seems like if you could build a system like this the energy consumption would be way lower than current electronics.
@@abstractumusic Only if we could connect these in series without capturing the result and 're-emitting it'. that's the key part, without that its as slow as the CCD-s.
Your videos are excellent and are making me want to go to grad school for optics, I don't know whether to thank you or send you a sternly worded angry letter.
I've always wondered about optical computing as well. Thanks very much for your video on the topic. Some ideas: I was recently reading about electrical memristors. Perhaps you could use photochromic materials as an optical memristor. I'm not sure if this would add an additional complexity or perhaps you could use photochromics without diffraction patterns to make a logic gate. Maybe also use polarization along the lines of "spintronics"? Looking forward to more!
Thanks for the suggestion Ben. If would be really nice if such a material could be sputtered or thermally evaporated as a thin layer on the evaluator side of the device. Because photochromics could introduce the non-linearity in the gate to make it behave in a more binary manner. Anyway, I'm not sure what is feasible for me to make. Looking into a concept is easy, but to make an actual optical processor would take many months of hard work...
Trying my best to not sound like a fanboy but I've learned quite a bit from both of you. Thank you.
@@HuygensOptics usually, it is an oxide film grown at hight T, it may be challenging to accomplish in a home-made sputtering/evaporation chamber.
I too am interested in optical computing, though I don't have all the fancy gear yet to start working on any sort of prototype but the ideas are there. If either of you 2 ( Applied Science/Huygens Optics wants to chat on some of them I am more then open for it as I would hate to see the ideas go to waste. Besides this project is probably much bigger than what a single person could do anyway.
why not to use radio/micro waves to prototype the paterns that works or not ??
I've had this idea floating in my head for a while as well but had no idea how it would be executed.
The optical lock idea is great and I loved the LPL reference.
These look fragile, I hope you never drop or damage you keys.
@@NicholasMarshall I am sure they could be encased in something to protect them, maybe a clear see-through resin for example. ( hopefully which wouldn't cause further issues reading the key )
This would need to be electronic no doubt. Just had an idea that is more robust. Why not use a usb key containg an ssh key? Should be impossible to "pick" or guess. If the software and hardware implementation is sound, it should be amazing!
CAT scan to the rescue !! oh wait...
@@Thor110 A resin could protect them from shattering but would reduce the number of 'pins' you could have (no matter how clear the resin is, it's going to diffract some light requiring more spacing and/or larger 'pins' to compensate). Resin could still potentially scratch as well which would make it useless.
That said the key could be incased in something a bit more solid with some foam to absorb shock, the 'pins' could be inset inside the 'tip' of the key (hope that makes sense) with a simple mechanical shutter that opens when the key is inserted so the 'pins' are only exposed when the key is being used (kind of like a how floppy disk or VHS expose their disk/tape when inserted). One or more of the 'pins' could act like inputs into the key which could actually make the keyhole a part of the key as well (not sure if that would be useful in any way), more importantly the source of light should come from the keyhole with the key being solid state. Obviously like any e-lock the keyhole would need to have a backup power supply and preferably a way to provide power should it's main and backup power supplies fail though I could see that being a potential weak point depending on implementation (need to not only prevent rewiring but also make sure it can't be broken by undervolting or overvolting it).
Optical lock: little flash on one, nothing on two...
"A little defocused on 1,024..."
@@sudocheese 😂
three is binding
@@ffxim dont you mean"3 is blinding"
@@shanewilson3653 3, ( light ) is bending 🤦♂️
Nice presentation. Many current optical logic gates desings are based on the 'inteference' principle, for example those based on MZI. Phase delays are usually tuned by changing refractive index of materials or the length of light path. The diffractive method may have some advantages in computation (not necessarily logic gates since interference gives more than that). You may be interested in the following two papers:1.All-optical machine learning using diffractive deep neural networks and 2.Deep learning with coherent nanophotonic circuits. These two looks quite different, however both are based on interference.
That demonstration sweeping through the focal plane just blew my mind. I had no idea you could so precisely control the angle and phase of light with a 2D pattern. The ability to use lithography makes this very scalable and repeatable. I can see a lot of possibilities in stacking layers.
The questions you raise in your videos always stimulate fascinating ideas about QM.
I was theorizing and looking up how an optical transistor could work. Then I found your channel. Great video!
Same
Also I.
Same
Literally just a few days ago
I am on my to a PhD on coherent combination of fiber channels and I was thinking about using the device for optical computation. Well keep you posted 😉
How'd it go?? I've waited a year. 😄
@@bertnorticus1662 Computing is not out of the question but let's say that the PhD got me well. You can see the lastest development of the laser by searching for the XCAN laser!
Which university ? In Paris ?
@@Madthrax23 Yes
@@DucBanal I passed my phd in UPMC, before the switch to Sorbonne ^^
I've always had cursory knowledge about the specifics of how electronics work, especially in computing... I'm more of an artist. Although it helps when thinking outside of the box.
The idea of photons instead of electrons has always intrigued me and has led me on a quest of understanding computing on a deeper level. Seeing you work on this is truly inspiring to see! Keep going!
2:27 Kudos for combining the right IC with the right schematic!
Just wanted to say, that analogue programming is an emerging field for machine learning. I am FAR from an expert, but I am sure that some data science firms would be happy to talk to you :p
This concept was part of my graduate work in the mid-1990's. A journal article in Applied Optics was published entitled, "Programmable optical logic systems using free-space optical interconnections."
then why aren't we using this computing methodology now? is there some hidden flaw?
Thank you sooooo much! I played with this effect about two years ago (used hair instead of those tiny patterns) and was totally amazed by how you can focus the light without a lense. The resources online are not too great on this topic so your video was a bliss for me :D
7:40 wow your idea of putting 3rd Beam for interference are awesome .
Absolutely fascinating. I'd love to see more about this, especially if it's possible to "chain" multiple of these gates in series. For instance, It'd be great to see a basic adder constructed in this way.
Yes, but would you lose so many photons that you would need to amplify the signal?
Just make repeaters, just like redstone
I have always had it in my head that we should be able to implement logical operations with photons, nice to see it actually come to fruition.
Super impressed! A couple of things come to mind:
1) the multi-lobed outputs 12:36 reminded me of QAM (Quadrature Amplitude Modulation) lobes.
2) the diagram in the lower right corner at 4:03 reminded me of the averaging functions of artificial logic processors.
I think you're onto something brilliant!
Good Luck!
It's been my long interest in trying to understand the concept of OPTICAL SIGNAL PROCESSING, which you speak and explain so marvelously. The ability to construct and implement it in real world-physical fabrication and use, sets my highest respect for your knowledge and tenacity to construct when others, white paper simulate. You are the bomb. The days of AT&T's Bell Lab research in optical / photonic / light wave for which journals I marveled, generated all this time asking and waiting ... "why is it taking so long to replace electronics". I now struggle in taking my unscientific knowledge, but having tremendous desire to proactively offset the financial pain from the rising cost and future decreased availability of secured energy- and design its practical use. ..You present the realism for someone like myself to attempt and implement its use for the common good. Thank You
Absolutely brilliant!
I love the intersection of ideas from theoretical physics and having the knowledge and equipment to conduct practical experiments.
Great job on the video production both the content and visualizations are excellent!
Channels like this one truly make me believe that we are in a gold age of citizen science. Keep up the great work!
This is incredible. I'm familiar with digital logic, but these types of optics are beyond my level of education. I've always wondered how optical computing would work.
0:32 Wow, just the other day i gave this explanation to my mom, but soon after i realized that the light can't cancel into nothing. I can't believe i haven't thought of that before.
I didn't take the time to look up a better explanation though, so catching it here is pretty nice.
Your mom asks stuff like that?
@@DasAntiNaziBroetchen No, but i explain them 😏
Congratulations on your work, I'm an engineer and I always imagined we'd have optical logic ports someday. Now I see that Chinese are already developing optical computers. I really enjoyed your work congratulations. That's the future
This is really cool. You need to find a way to get rid of any frequency / phase shifts introduced by the "light logic gate" itself, this is the holy grail. Because then you can build bigger blocks without the need for massive error correction.
For that it would probably be nescessary to use patterns with sub-wavelength dimension. However, it is not all bad. There are also ways to use these phase shifts to your advantage....
@@HuygensOptics I think with e-beam lithography you can achieve this, but it is time consuming and you would need a stm and a beam-blanker of course.
To build something like a computer you have to be able to put gates in series. Use the output form one gate as the input to another without going through an detector and diode laser.
This is such a fascinating concept. I have imagined optical computers based on hexagonal crystals with the optical operators on the hexagonal faces and the data on the end faces with the output data being through an optic fibre cable for conversion to standard electronic function elsewhere. There are so many fabulous mechanisms such as using air (vacuum) gaps to allow past data to jump ahead of current data, optically clear piezo electric crystals to deflect beam direction, and photonics devices are beginning to appear. The prospect is to build fast computers that are immune to EMPs, but also have indefinite life to store the history of our civilization beyond its inevitable collapse. Keep going, this is huge.
I concur, EMP is a huge issue, if the world would know that all the electronics of an entire country can be broken in a few seconds with EMP, they would never use silicon chips
I know what I will do when I studied physics (another life) and am in my pension. The same thing you do, this is super interesting, I'm glad I subbed, you're brilliant IMHO
so cool! when i heard about all the strange non-linear optical effects certain materials had I got straight to thinking how they could be used to build gates. w/ Raman amplification and cross-phase modulation, you can basically build all-optical transistors. optical phase conjugation just blows my mind.
Yes. A mixed optical/electric system would give you a low heat processor. Of course, it might be a tad large, but low heat is worth that.
The need for a Flip Flop is paramount for computing.
I believe there is a crystal that change opacity to a certain wavelenght when lit with another wavelength.
I think it was in an experiment about stoping light.
If you have 2 crystal that behave in opposite way, first one is clear to booster wavelength when activated by signal wavelength, the booster wavelength allows signal light to be set clear, which keep the first crystal clear...
It could then be latched off with destructive interferance.
I might not be clear, but it might still help
As he points out, state based switches for read/write memory are way more important than the computation. It's all arbitrary unless you can, how did you put it, flippity-flopp.
Yeah I was thinking about how to do some sort of latching. Idk, maybe latch data between 2 mirrors in a laser with a way to optically turn off and on the laser. That way data could be latched in, and continuously pumped with the laser medium. No idea how that would be done. I suppose to design a data flow engine, latching is not required. Analog data flow engines with op amps don't seem to require latching data (things just flow in one side and results come out the other). In order to run software I would imagine you would need some way to latch bits or chunks of analog streams. I would have to turn on my brain to think about the minimum requirements to run software which I'm not prepared to do rn. Sounds like work.
@@Personnenenparle That would be cool.
I think the crux of the problem is that with only superpositions, I don't see how it would be possible to implement anything like a mux or flip flop. If you could use intense light to make pits in glass like a rewritable CD, and if you can boost the light's signal, then I think it could probably be done, but it would be quite slow compared to any normal computer, and I don't know how many times glass like that can change phase.
Woooow this is actually something I have been working on for many years! It is interesting seeing someone using interference! I had only considered using it for developing a not gate, my work has mainly been around taking advantage of optical filters and defraction to reflect and change colours of lights in order to produce gates. I have always thought taking advantage of light for its colour properties would be the way, but what you have here is far more impressive! Would love to see more!
Okay....this is awesome.
I'm excited to see the first optical flip flop
yep! the only thing left to fully unfold photonic computing and make it available to the masses
I think "why i make a basic calculator worked by colors" and you appeared before me... its unbelievable think mate its very cool. And homemade CPU, its fantastic!!
Very nice work. I had a related idea a while back to "compute" by convolution at the Fournier plane. You might find some happy rabbit holes to go down with this method. Basically compute the fwd FFT of the logic you wish to impart, and then etch that as a mask.
Only recently discovered this channel (thanks to the double slit experiment video), just finished watching everything you have here. Liked it very much! Maybe i'll go sort through my tiny box of salvaged optics now...
it's going to be very hard to chain these gates, considering each of them outputs light in a different polarization state depending on its inputs.
He presented a very interesting parallel processing architecture towards the end. A matrix of inputs exists on one side. The inputs would be loaded from a memory cache. The inputs go through a matrix of generators and evaluators. The output is read by an optical sensor. The memory cache is updated from the values read by the optical sensor. This process repeats in cycles. There would need to something that reads and writes to the memory cache. In this way a program can be loaded and evaluated, and the results read. This is a very cool concept!
The process is not too dissimilar from a frame buffer on computer graphics. Frames of data could be preprepared ahead of optical processing. The frames get added to a processing queue that gets processed FIFO by the optical processor.
How does an erbium doped amplifier affect the polarity of light? Sorry if this is a dumb question I'm very new to optics
Fantastic!
I heard Apple or IBM was working on an optical computer several decades ago, but never heard anything more about it.
Interesting idea. I’m imagining a glass cubed cpu with optical fiber inputs and outputs. I think we will be using light for general computing sometime in my lifetime. It’s getting too expensive to make the latest processors using semiconductors.
Especially for AI inference, computing could really benefit from being done entirely digitally in light, including logic gating and memory.
I remember a family friend who worked at Lucent telling me that they were working on a fiberoptic network switch that would direct the flow of traffic without media conversion. No copper. I wasn't able to tease an explanation out of him (that I could understand, dunno why was telling a kid my age something like that anyway) and I've wondered about it once or twice a year ever since. I think I've finally got an answer to that question that I understand, thanks.
You earned my subscription with this video, this is so exciting to see such a creative approach.
Oh my! You, Sir took me back in 1995 when I have envisioned a similar approach! I have a Word document in an old hard drive somewhere! If I find it I will send it to you!
You should try to create an optical transistor, where the input doesn't come from the other sources but a third that controls them. And maybe a two sided device that makes the light go back and forth.
Transistor with 3 sources? And no destination? Type-2 nonlinear crystals give you polarisation as a way to separate two sources.
add sensors at both destructive and constructive points to give a ratio output, use log amps to help digitize, allows more precision over a much larger bandwidth of light level variations.
etch the outer ring of interference filters on the other side of the glass to get back your genius win. make the thickness correct for height delta to re-align focal points in space.
poppa was a photon magician, learned this stuff in the back seat of a station wagon.
great videos.
your tesla valves can be used to generate water level differences.
This can be used to measure flow direction and pressure differentials with fluid induced optical path changes.
This can be used as a logic device for flow control and measurement
this was recommended to me. Its incredible.
Also i wanna see you partnering with some metal worker on yt to make that lock a reality to finally defeat LPL
Excellent. I've been wondering about using optical wave interference for making optical transistors for a long time (probably a million other people have invented it in their heads as well). I considered capturing the wave peaks and using that light in the next transistor, but thought you would perhaps need amplification to have enough photons. Goods that this idea is being shared as someone might gain me insight to actually building a optical computer one day.
Have you explored polarization as the logic level as opposed to interference based intensity?
If you could use left and right hand circular polarisation the system would become immune to phase shifting caused by thermal expansion which would be quite useful.
@@zyeborm I've always wondered if it would be possible to basically add or subtract 2 wavelengths from each other and use that for math within a processor (hope that makes sense). Not sure how to handle logic with such a system though (maybe use a specific set of wavelengths that have this sort of constructive/destructive behavior).
@@grn1 yes maybe with Fourier transforms, i was thinking of an analog computer based on wave arithmetic.
I've thought about optical logic using optical ring resonators a lot since I saw a presentation at a RISC-V conference a few years ago. Ring resonators seem to be pretty trivial quantum devices because their boundaries are easy to understand, leading to interesting yet comprehensible topologies. Anyway, every time you release a video, I hope that you talk about photon sieves again and lead into clever applications for computation. Thanks for the interesting video in the meantime!
Destructive interference places the light somewhere else. How important those words are. First year physics teaches that photons cancel each other out, or it did in my day. Thanks for saying it, even if I change around your exact quote.
This is uncanny, I was thinking about the same thing for 3 to 4 weeks now, googled it just as yourself and only found this video today.
"truly unpickable lock"...
LPL: Hold my beer
yeah thats a no from me chief, lol
and locks NEED to be pickable, otherwise if you lose your key you'd have to break down your entire door.
@@razhemo4191 Don't loose the key, then.
@@junosoft that's easier said than done lol
@@junosoft /r/wowthanksimcured
@@razhemo4191 They don't need to be pickable: when locksmiths cannot open a door through low-effort means, they just drill the core out and replace the lock. If I put in a lock strong and secure enough that breaking down the whole door is the only way to get in, chances are that requiring this degree of effort was the whole point of putting in such a strong lock in the first place.
Pure optical switches, and LCDs/LEDs where my first thought on the topic of optical interference
That lock idea is brilliant.
I'm sure LPL would have a great time
Realistically speaking, if going down the route of electronic locks, I think a fully enclosed RFID lock would be strictly better. Not as fun, for sure, but better.
@@chuuni6924 "better" only depends on how difficult it is to spoof the signal it wants to open.. An electro-optical logic gate lock would take a fantastical amount of effort to non-destructively open
@@SuperAWaC Cracking an AES key would also take a fantastical amount of effort. Certainly, there are more and less secure RFID protocols, but as long as you're doing electronic locks, I'd trust properly implemented cryptography over virtually anything else. Now, if you could find a way to implement this optical key in a manner that didn't require electronics, that'd be a different thing altogether...
@@chuuni6924 There is a video where they use a child's toy to hack the signals in garage door openers. I think it was Veritasium. It was pretty eye opening.
@@Robert_McGarry_Poems Yeah, that video is a great example of crypto not properly implemented (or not implemented at all, as the case may be).
Wonderful demonstration and explanation! If you consider polarization as well in to it, you will get more bits in the gate!
The idea of a adding a third always-on beam is ingenious. It's also absolutely necessary for creating a NOT, otherwise there would be no light for a "0" source. :)
is it really ingenious it that's literally how transistors work?
Yes, transistors are ingenious. :)
Wow! I thought of the same idea 20 years ago in high school but didn't know how it could be implemented. I'm glad to see you giving it a shot.
I remember years ago pulling apart a cleverly engineered optical keyboard, it had a row of lights going down channels to led detectors at the other end. Each key had plate that would interrupt the light channels thus producing the ASCII character code for the key pressed. So you could implement a full optical computing system from input to logic and then work on optical output- wouldn’t that be cool.
The treason to build optical computers is for speed (single core or parallel processing). The optical to electron conversion is slow and bulky. We need photon switches that are mechanical/electron independent.
I was also come up with a very similar implementation for the optical logic circuits few years from now, it's very nice to see it practical implementation.
The time traveler!
42...
I wonder if there would be any benefit in trying to make zone plates with smoothly varying sinusoidal opacity, instead of the usual fully opaque and fully transparent stripes.
I don't know how small you can get your details with your lithography setup, pretty small it seems, :) but perhaps you could use a sub-wavelength dither or sawtooth to transition between opaque stripes and transparent stripes.
If I recall, moth's eyes do something similar to this, but in three dimensions. Their eye lenses don't have smooth glass-like surfaces, but rather the surfaces are blanketed with an array of sub-wavlength cones at sub-wavlength spacing, which the longer wavelength light treats as a gradual transition from the refractive index of air to the refractive index of the denser eye material. This gradual transition helps reduce the loss of light to specular reflection, making the moth's eyes more efficient.
In the case of zone plates, you'd be creating a similar effect in the 2D zone pattern, by incorporating a sub-wavelength drop-off pattern in the opaque material as you transition out of opaque stripes into transparent stripes. If you could get the effective opacity to vary sinusoidally, then you'd have a zone plate that behaved much more like the pair of touching glass blocks you showed at 0:15, in terms of smoothly varying transmission and reflection stripes.
This sinusoidal zone plate pattern might also help reduce the higher order additional focal points.
Anyway, just a thought. Fantastic channel by the way. :)
Making gradual phase changes in the rings of zone plates can definitely improve optical performance. This is basically what is achieved in high-resolution meta surfaces.
This is surely very interesting. The next step would be an optical flip flop and an optical synchronous counter.
Very interesting idea using interference, but I still can see how size might be a problem.
TL;DR: Ordinary optical components are linear, and no combination of linear components can produce a non-linear device. XOR is non-linear.
Optics is a wonderful field, and your craft and hand-on demonstrations are very beautiful, and a pleasure to watch. I certainly am not writing this to criticize you in any way, but merely to point out some fundamental considerations to be aware of.
Ordinary optics (meaning a fixed arrangement of lenses, mirrors, diffraction gratings, filters etc) is *linear* in the sense that if an electromagnetic wave "A" at the input produces the output "X", and an input "B" produces the output "Y", then any mixture of A+B at the input produces a corresponding mixture of X+Y at the output.
A Fourier transform is a linear operation, which satisfies the above property. Hence, it can be realized by an ordinary optical system. (Any other weighted sum or difference of inputs can also be realized.)
But a lot of interesting computation is *not* linear or reversible. XOR is already very nonlinear! Threshold that is inherent in all of the ordinary electronic logic gates, even in inverters, is a non-linear transformation. Obviously, multiplication and division are non-linear, etc, etc. Finding roots of a quadratic equation is non-linear. Almost any computer program is extremely non-linear.
In general, universal computation fundamentally cannot be realized with just the linear elements (the ordinary optical components.) To make a universal computer, one would have to add non-linear optical elements into the system. Such nonlinear optical elements do exist and are used occasionally to great effect (frequency doubling, for example, like in green laser pointers), but as of yet there is no easy to use, inexpensive non-linear optical element that would be equivalent to a transistor.
With the ordinary linear optics, you can make a linear mixture of the inputs that resembles some logic operations. But without sneaking in some non-linear operation, no matter how you cascade these linear blocks, the result will always remain a linear system, and some even very simple things like XOR will not be even approximately realizable.
There are of course great many other things that only optics can do. Good luck with your experiments -- love your work!
Fantastic work! Very nice explanations and video quality! Looking forward to the next one :)
very few people they have the charisma to CREATE technology.... tesla it was one of them . if you have something like this i really wish you to succed .. you have my positive energy and my best wishes.
*@Huygens Optics*
12:41 What happens if you make this a spiral instead?
Each revolution it goes 1 "band" (white to white) outwards.
It changes thickness according to whatever the thickness you use at any radius here.
It seems to me that development of the refractive patterns would be helped along by an accurate computer simulation of the behviour of light waves and a genetic algorithm to spawn a multiplicity of potential patterns. A genetic algorithm would possibly get you to patterns that you would never have considered.
Fascinating video..is there anyone who dosent watch LPL ?
The man is the biggest advocate of open source housing.
I'm currently working on running simulations for optical neural net components. Good to see more people are considering the potential in integrated photonics. I don't know if interference is the right strategy though considering the difficulty of getting interference on chip with enough nodes.
0:46
The explanation actually makes perfect sense.
Destructive interference does not destroy the EM energy, but two waves of equal amplitude and opposite phase will not have an effect on the rods or cones in your eyes, or a light sensor in a camera. Both rays of light still reach their destination but cannot have an effect because of their evil twin.
I think you misunderstood there. The electric energy is not secretly there, but "undetectable" or "unabsorbable", the energy literally does not go there, but somewhere else.
If you make glasses anti-reflective more light goes through. The light isn't "silently" reflected.
I do not understand why it does that, but it is doing that.
(Please correct me if I misrepresented your understanding of the topic, it's the educator in me talking)
@@CXT14GamerMouse
🤔 Hmm.
So if two coherent laser beams of equal amplitude, and wavelength, but opposite phase were fired into my eyeball,
they would pass right through my retina? Continuing ad infinitum into the sunset?
Now I'm confused 😂
I just assumed they would both be absorbed but only as heat
@@Jeremy.Bearemy The light would not even go into your eye, the interference would make a pattern offset from your eyes. In your contraption the energy would again: go somewhere else.
I don't have the skill to give an explanation which is not false in the context of a youtube comment, I would probably struggle if I had a whole week. I would love to teach you, but I think you are on the right track. Just keep me in mind the few next times you watch interesting videos about light and try to accept my premise.
You will see how it fits, and how light is always weirder than you think.
I wish you good luck and stay curious :)
You are certainly onto something here. The Canadian company Xanadu quantum is working on a similar way to use integrated optics for quantum computing.
I loved the reference to the lock picking lawyer :)
this looks like some fun experimental technology, I would like to try this out.
Very cool!
Hey u cool too! Jus dont crack my pc!
samy is my hero!
Hi Samy
I was working on this process and the application of this process as far back as more than 9 years ago, but less than 10 years ago. I was working on redundancies to allow for full application of this process in the form of hi speed primary memory and processing logic at least as far back as Fall of 2019. I had concepts for mitigating waste heat and recovering waste photons, etc. One of the immediate advantages of this process is that you can make an optically actuated clock, and with negligible difference in waste heat production, run a hypothetical cpu, or bus, or memory at several orders of magnitude faster switching/clock speeds than the viable ceiling in semiconductor processing(mitigating the problem of gates operating in the shorter end of the x-ray band having slightly longer delays than is applicable in the best viable semiconductor gates, and especially applicable if working with uv light - which is more immediately testable ). I had strategies for approaching the prototyping and testing of a drop in replacement for ram in sodimm form factor, but needed to wait until I had more resources for fabrication.
Imagine a massive fpga array that occupies almost no space, has 1/1000 the latency of a conventional fpga array, and consumes 1/10 of a watt?
It is hypothetically possible to create a switchable diffraction array in multiple physical planes of interaction that can be intermittently changed to affect diffraction of indefinitely many poly-degree layers of diffraction/interaction. In other words, there is a straightforward path to making a processor that can physically change it's architecture across extremely short timeframes.
This is amazing! This is something I’ve been theorizing my self and I love what you have here! Your validating my theories!
About time! Enter the new age of holographic computing! Been waiting for someone to get a clue on this for 30 years now.
Need a way to amplify the signal without using CCDs and LEDs. Logic gates aren't just switches, they also amplify the signal to keep the fan-out.
What about a doped fiber amplifier?
Fibre-optic gyroscope use interference also. I do not know much,
but maybee here are some good ideas, how to split and combine two
beams. this topic is very fascinating. thanks for sharing.
As I'm sure you're aware, all logic gates can be built by series of XOR gates or XAND gates. So if you can produce a very simple and reliable XOR, you have everything you need to build arbitrary microprocessors!
You need memory too.
Is it possible to make a flip-flops?
WRONG! First of all, there's no such thing as "XAND", the opposite of XOR is XNOR. What exactly is an exclusive and gate in your mind and how is it different from an exclusive or gate? Think mcfly think! But the only thing you can make out of a series of XOR gates is..... more XOR gates, or XNOR gates. The term you are looking for is "turing complete", and the only 2 logic gates that are turing complete are NAND and NOR gates. To Cristian, to your comment, you can make flipflops out of nand or nor gates, by having a pair of them with their outputs led back to one of each others' inputs, and that gets you your memory, that's why you can't do it with xor gates, because it doesn't work to feed their outputs back to their inputs.
Great video! An un-picable lock. Brilliant. You should file for a patent on that if you are the first, or at least write a whitepaper and have it published - even on TH-cam if no one will pick it up. Optical computers, this is very stimulating (no pun intended). If you could do this with individual photons, quantum computing may merge with this. For those of you not familiar with digital logic gates: In electronics, all you really need is NAND gates because a 2nd NAND gate (with one input tied to a logic '1') on the output of the first acts as a NOT (inverter) gate and converts the NAND gate to an AND gate. So, using NAND gates, you can make: NAND, NOT, AND, OR, NOR, EXCUSIVE OR, EXCLUSIVE NOR, and any other gate with various combinations NOT on the inputs and output... and you have ALL the building blocks of computer logic. With Optical Logic, you start OR and NOT gates, and those too can be combined in various ways to create ALL of the same building blocks gates used in electronics. For example: Demorgan's Therom states you can convert, say an OR gate to an AND gate by putting a NOT on each input and output of the OR gate. Try it: The truth table of a Negitive Logic OR gate (one with NOT on the all the inputs and output) and truth table of an AND gate, both tables give the same results with respect to their inputs (thus the same gate, just inverted "logic/polarity" symbols). A postive logic AND gate is the same as a Negative logic OR gate, they do the same but you look at the logic from positive or negative perspectives, so the symbols are different but do effectively the same.
Interesting, I've been tooling around with the idea in my head for a while. Should be a good video. =)
Edit: Ok finished the video. This is similar to what I was thinking. My idea was based upon the double slit experiment and you'd basically fire two beams of photons (one beam per slit) and if both were on, you'd get photons in the center of the diffraction pattern at the "aperture", so basically an AND gate.
I hadn't really worked out the NOT gate yet but once that was figured out you could build a NAND gate and then from there since its a universal gate you could build any of the other logic functions; OR, XOR, etc.. and well... things just progress from there. Sure since everything is NAND the gate count goes up, but given the speed at which it would run, I don't think one would care until you're pushing the limits of the technology.
One concern if chaining gates along to form logic and computational units is the attenuation of the light going from one gate to the next. Since the light is diffracting I would suspect some photonic loss at the aperture. So at some point you'd need a signal booster of some sort.
This was one of those things where I figured if I had thought of it surely someone somewhere else much smarter than I had already thought it through and determined it wasn't viable and hence why we don't currently have the technology. =) But hey, maybe there's something to it after all?
It's certainly interesting stuff.
Thanks, you have clearly given it a lot of thought. I myself thought that this type of configuration would be well documented by others. But what you see is that efforts are mainly directed to "in-plane" configurations, so that processing is more compatible with IC manufacturing. And you are right about the efficiency. With every diffractive element, you loose at least 50% of the light. But with a limited number of layers, I guess light intensity loss will not be a very big issue.
@@HuygensOptics That’s where I think that building an optical key sounds like a good idea.
Electricity is just too good at running electronics since it is just so easy to use changes in magnetic fields to flip relays or charge up capacitors or quickly change the properties of P-doped transistors to allow other current to flow. What you basically need for a photonic circuit to be as good as an electrical one is to find some way to have light particles on one side of a transistor cause the other side of the transistor become transparent (and then become opaque when no light flows, or Vice versa) in order to avoid needing to revert back to electricity to control the flow of light
@@HuygensOptics To address the attenuation problem, I suppose you could pass the output of the logic gate through a laser cavity with the end mirrors removed (i.e. utilise the Light Amplification bit of the LASER acronym) - to get more amplification you could fold the beam through the cavity a few times. Perhaps a dye laser would be suited to this - obviously the laser would have to have the same wavelength as the amplifier. Possibly you could use a single cavity to amplify numerous beams. But I suppose if you have a long beam path you would end up with optical logic that is slower then current electronic logic.
@@johndoggett808 even if it were slower it would still have uses. A solid state computational device that's immune to electromagnetic interference would have many uses.
@@zyeborm True
Hi!
I love the idea of optical logical gates as well as logical computing using interference like this, and the demonstrations in this video are really quite wonderful to look at :)
However, I think that this type of logic gate can not work in larger systems.
The reason for that is that the way the light is combined is purely linear. This means that when switching multiple gates behind one another, the result is not a nice and clean 1 or 0, but rather some linear combination of the outputs - it always has to be an addition of the wave functions.
An "OR" gate, for example, can not just output 0/1, but rather 0/1/2, and you would have to deal with the different phases of the output signal of the XOR/XNOR gate before feeding it into the next gate.
Some sort of nonlinearity has to be used to break this linear combination and provide true logic gate functionality.
The unpickable optical lock looks like a worthy challenge for everyone's favorite lockpicking lawyer.
Reminds me of the _unpickable_ tubular locks
Diffusing Silica (glass) on other layers, you could make micro fiber optic paths to connect the gates together. And, if diffraction patterns could be introduced in these fiber/optic paths, they could combine at an aperture - that would eliminate need for the diffuser layer as this would be encoded into the paths themselves resolving into logic functions where they come together at various aperatures.
hahaha took me a while before i understood the LPL shoutout, very nice
Ok. I’m using my 100micrometer shim
to provide tension. Constructive interference on gate 2. Gate 3 feels like it’s in shadow. That’s a click from gate 4. Back to gate 1.
"but unfortunately this lock has around 100.000 gates which all have to be in the AND state for this lock to open. So instead, lets get the Ramset"
@@superchromat A little binding on gate 55,763. 🤔
Very cool stuff. I think the real promise of this type of circuit is in power savings and parallelism (multiple wavelengths, each representing a different set of inputs, could potentially be run simultaneously through a single circuit). BUT, I'm not an optics expert.
How do you plan on normalizing outputs again so you can use multiple gates in series?
Exactly my thought as well!
Even though it has been shown to work in isolation doesn't mean it will be feasible to use in series.
This could be applied to perform complex hard-coded calculations, so in a way it could shorten the instruction pipeline of a CPU -- though I don't think the conversion from electrical information to optical and back again will be faster than doing all of that using the same data source.
I think it might be significantly easier for you to use edge based diffraction gates so that you could lay out your work with more ease. The way that might work is by reducing your optical path from planer to a linear. You could use glass etching techniques to create fresnel lenses that are phase based, and with the optical paths that are through the edge of the plate, rather than normal to it. Furthermore, using phase based diffraction elements allow you to increase your optical power in the first order lobes of your pattern significantly since it won't be lost to the DC angular plane waves you have to deal with when using purely absorvative filters.
Furthermore, reading bens comment about using photochromic materials to introduce nonlinearities/memory gave me the idea that you could selectively sputter these materials into wells created by glass etching, which would allow you to place pockets optically nonlinear material!
im not procrastinating. Im taking a better class.
Best comment
Well typed
The problem is that light is (generally) linear. You could talk about these as individual gates, but if you actually connect them together, no matter what you do the final result will be a linear combination of what you started with. You can't get complex logic. Not unless you add something to make it nonlinear, like having a light sensor that triggers a laser. There are ways to do that, but I think that's the interesting part of the problem that needs to be focused on. Not something you can just ignore.
The only gate you actually need to be able to make is the nand gate. All others can be built from that.
What if size matters?
I am a EE from U.C.Berkeley. This is quite interesting. Will research this more.
Making more logic gates in the same area as we currently have and power them with UV/Vis light will be really hard.
But they are faster and less limited than electronics, so you can get more milage from a similar arrangement. LED would be optimized for it's circuit. Because you couldn't directly link them all together, each circuit could have a differently tuned LED source, specific to it's purpose.
Very exciting work, having watched the earlier elements you presented I was left wondering where your mad genius was leading ;) Wishing you the best of luck and may the photons be kind to your research.
is the exclusiv or gate not called XOR?
i never heared of EOR
Me neither
Whelp, if you've never heard of me I guess I'd better just wander on back into my hut. Not that it matters, I'm not really much of a donkey to hear of. 😶
I've seen it called EOR, but only by electronics engineers. In software we always call it XOR. EEs seem to use either or both terms.
very cool bro,
wanted to make it like couple of years ago, but couldn't implement due to lack of access to optics and time, any way just wanted to tell you it is very cool that you are doing it
I remember designing something back in the 90s that required an LED to flash 10,000 times per second, and I ran into the problem that the LED would remain glowing for many microseconds after it was no longer powered. (Maybe LED technology has moved on.)
nah m8, led technology has remained stagnant since the 90's
Awesome video, the concept and execution shows that this idea could be further developed (and maybe miniaturized). That would give a whole new meaning for optical devices
It looks like a shitload of energy is being lost on each gate.
True but think about how much energy is in light at that scale compared to that of electricity in current machines. It seems like if you could build a system like this the energy consumption would be way lower than current electronics.
@@abstractumusic Only if we could connect these in series without capturing the result and 're-emitting it'. that's the key part, without that its as slow as the CCD-s.
Your videos are excellent and are making me want to go to grad school for optics, I don't know whether to thank you or send you a sternly worded angry letter.
Written with binary, in interference patterns... 🤣
Oh man! Please make a full episode extending from 2:15. Plz!
Well, I will definitely return to that particular subject in a future video.
What a fascinating video. Thank you so much for sharing your studies in this format!
Отлично!!!
A very well illustrated video with concise narration, a really good job! 👍👍