Making Optical Logic Gates using Interference

In this video I look into the idea of using optical interference to construct different kinds of logic gates, both from a conceptual- as well as from the practical perspective.

Contents
0:00 Intro
2:15 Logic gate operation
3:36 Optical logic gates
4:45 Concept of a diffractive logic gate
7:52 Practical aspects (photolithography and etching)
8:46 Wave front observation method
9:20 Results
13:51 Possible applications

Webpage with detailed and complete information on logic gates:

The diffractive patterns were made by using a home-brewed windows Zone plate app and then modifying them further with photoshop. The Zone Plate app can be downloaded from:
For Windows 10 and for personal use only. Virus scanners and Windows will nag about it being a rare / unknown file and make installation sometimes difficult. Sorry about that. Install this app at your own risk.

An overview article on various known optical logic gates can be found in this paper:
However it does not contain any mention of the configuration described in this video

The video contains references to detail videos on the following subjects:

[AppliedScience]

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!

[bf]

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.

[zhifengzhang]

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.

[bartomiej]

Optical lock: little flash on one, nothing on two...

[DucBanal]

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 😉

[DawnOfTheComputer]

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.

[BloobleBonker]

The questions you raise in your videos always stimulate fascinating ideas about QM.

[DeadLikeYou]

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

[MadScientist]

"truly unpickable lock"...

LPL: Hold my beer

[danieldossantos]

I was theorizing and looking up how an optical transistor could work. Then I found your channel. Great video!

[jojodi]

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.

[KeeperOfKale]

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!

[TheEvertw]

2:27 Kudos for combining the right IC with the right schematic!

[VirtuelleWeltenMitKhan]

Okay....this is awesome.
I'm excited to see the first optical flip flop

[scifactorial]

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!

[PatrickSalisMEDIA]

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

[eggburtdilusia]

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!

[mikeyjohnson]

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.

[thewokal]

Thank you 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

[roderick.t]

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."