NIST scientists create 'any wavelength' lasers (nist.gov)

by rbanffy 193 comments 421 points
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193 comments

[−] nabakin 26d ago

> When it comes to information transfer and processing, light can do things that electricity can’t. Photons — particles of light — are far zippier than electrons at working their way through circuits.

Electrons themselves don't move at the speed of light, but information transfer (i.e. communication) via electrons does happen close to the speed of light.

A subtle, but important, distinction that's often misunderstood and means computational performance gains would probably come from bandwidth, not latency.

[−] Hikikomori 26d ago
About 0.6c for cat6 cables, different types of cables can be slightly faster. Speed of light in fiber is also 0.6c due to the refractive index of the core.
[−] derefr 25d ago
Is that through solid-core fiber? Because hollow-core fiber also exists.
[−] Hikikomori 25d ago
Yes. It does, but it's not widely used, it barely just got out of the lab.
[−] thayne 25d ago

> but information transfer (i.e. communication) via electrons does happen close to the speed of light

Speed of light in the medium, not speed of light in vacuum.

[−] NL807 26d ago
In electric circuits, information is transmitted through the electric field, which itself is close to the speed of light.
[−] tempaccount5050 26d ago
Nope, it's 1/2 - 2/3 the speed of light depending on the metals used.
[−] KK7NIL 26d ago
The velocity factor is usually 0.6-0.7, never seen it as low as 0.5.

And it's set by the dielectric, not the conducting material.

[−] spwa4 26d ago
You're both wrong. It's true that the first whisper of movement travels at the speed of light, but the time until the flow stabilizes (which you WILL need to wait for in electrical chips) is actually slower than the "speed of electricity".

Oh and also: currently the idea behind on-chip lasers is interconnects that don't have this limitation. For example, PCIE is looking to build optical interconnects, which will do the equivalent of bringing every GPU 10x closer to the memory.

Optical computation would require that light switches light transistors on and off, which doesn't seem to be possible with this technology. This is optical computation in the sense of allowing light beams to be produced according to formulas.

[−] BenjiWiebe 25d ago
Why do you need to wait for it to stabilize? You can keep changing the voltage at one end of the connection even if you have megabits of data currently in transit, without waiting for it to stabilize. Yes, you'll need to do impedance matching. Yes, that's a solved problem. Transmission lines.
[−] sbuttgereit 25d ago
Looking at the discussion below this comment, I'd just add this video by AlphaPheonix:

https://www.youtube.com/watch?v=2Vrhk5OjBP8

Good discussion in the comments there as well.

[−] dtgriscom 26d ago
That picture of the wafer with a rainbow of shapes is very misleading. It suggests that the various colors you see on the chip is the various colors the lasers can emit, which is wrong; it's just diffraction, and has nothing to do with the topic of the article. (But, PR people gotta PR...)
[−] protontypes 25d ago
In fact, regular tunable wavelength lasers do work with diffraction gratings. https://www.edmundoptics.com/knowledge-center/application-no...
[−] adzm 26d ago
Everyone talking about magenta and brown, but you can see an illusory color right now even without lasers! https://dynomight.net/colors/ behold, some kind of hyper-turquoise
[−] jcul 26d ago
The whole idea of colour and light frequency is fascinating.

These are just frequencies of light, but the subjective experience of them is so much more.

And the whole thing of my perception of "red" or what I call "red" could be very different to someone else's subjective perception. But we would both call it red and associate it with the same thing, fire, love, heat, danger etc.

[−] sgc 26d ago

> what I call "red" could be very different to someone else's subjective perception

It's worth noting that is true of virtually everything we know. >>This is a very simple sentence.<< Anybody who understands English, 'understands' it. But what it means to understand it is perhaps completely different for each person. As long as they fit into the same place in their worldview (Lewis Caroll's Carrollian syllogisms come to mind), practically it often doesn't matter beyond recognizing the wonderful uniqueness of each human being. Likewise, unless somebody is color blind or perceives more colors than others (tetrachromats), it doesn't matter since the relationships between the different concepts or colors will be analogous amongst most people - so a common understanding within the differences is possible. Or perhaps it is more precise to say that there are so many data points in color perception or anything we know, that despite the minor differences in relationships, we understand each other because the differences must be minimal given the practically unlimited data points constraining our perceptions. In fact, when people's perceptions of things vary too much, they can be classified as mentally ill even if they understand many things perfectly well.

[−] sysguest 26d ago

> As long as they fit into the same place in their worldview

but... "same place in their worldview" model goes awry when things to slightly off course

most people are ok with calling rgb(255,0,0) red, but some will argue with rgb(200, 50, 20)

[−] patapong 26d ago
At the same time, there's some commonality for what words mean in different contexts. For example, even though we all have our own experiences with the concept of "dog", there's a common core where we have enough of an understanding what other people refer to as "dog" to allow discussing the concept. Likewise, for most people, dog is more similar to cat than to house.

Imagine if we could build a machine that reads a bunch of texts and tries to extract this meaning by looking at which words commonly co-occyr with other words in different contexts. Perhaps something interesting would happen...

[−] TheOtherHobbes 25d ago
Yes, but the qualia could be completely different and we'd never know.

For all I know you don't just have a completely different experience of red, but a complete different experience of geometry and spacetime.

Your subjective experience of vision could be a mirror of my own. But we'd both still associate "right" with the same half of the body.

You might not "feel" curves and lines the same way.

As long as everyone's mappings and weights are identical, the qualia themselves could be anything.

We assume the qualia would at least be recognisable, and they can't be too different because there has to be a common core of experience categories, with recognisably consistent relationships.

But beyond that - anything works.

This isn't a hypothetical because once you get into politics and ethics, the consistent relationships disappear. There are huge differences between individuals, and this causes a lot of problems.

[−] da_chicken 26d ago
I think it's important to remember that we're not perceiving some fundamental aspect of light. We're perceiving how the photosensitive portions of our retina convert light to stimulus, and how our brains construct a meaningful image from that stimulus in our mind.

Like film photography doesn't happen in the lens or the world. It happens in that photosensitive chemical reaction, and the decision of the photographer.

[−] d0mine 26d ago

> how our brain construct

is the only part i.e., we perceive what brain predicts no more no less. Optical illusions demonstrate it well.

Sometimes that prediction (our perception) correlates with the light reaching the retina. But it is a mistake to think that we can perceive it directly. For example, we do not see the black hole in our field of vision where there are no receptors (due to our eyes construction).

Another example that makes the point clearer: there are no "wetness" receptors at all but we perceive wetness just fine.

[−] nkrisc 26d ago
It’s an important point: all our sensations are interpretations of readings from various sensing abilities.

Which is why it can be so easy to produce false sensations of many things. It’s like tricking your fridge into turning the light off by pressing the little switch instead of closing the door. The fridge isn’t detecting when the door is closed, it’s detecting with that switch is pressed and interpreting that as meaning the door is closed. However that interpretation may not always be correct.

[−] TomatoCo 26d ago
It reminds me of how vinyl records are fairly lossy, but they provide a superior experience in some cases because those limitations have been accounted for during the mastering process.

It's an entire pipeline from photomultiplier to recording medium to the inverse process and everything is optimized not for any particular mathematical truth but for the subjective experience.

[−] com2kid 26d ago
Vinyls are sometimes preferred because people like white noise, same as tube amps.

Granted some CDs are mastered like garbage, and that led to some bad press for awhile. But you can master a CD so that it sounds exactly, as in mathematically exactly, as a vinyl record, if so desired.

It is also possible to make a digital amplifier that sounds exactly identical to vacuum tubes.

Humans have well and mastered the art of shaping sound waveforms however we want.

[−] XorNot 26d ago
I mean I've always thought the kinetic experience of vinyl was the point: my childhood memory is the excitement and anticipation of carefully putting the needle on the lead in and hearing the subtle pops and scratches that meant it was about to start.

The whole physical enterprise has a narrative and anticipation to it.

[−] dotancohen 26d ago

  > carefully putting the needle on the lead in and hearing the subtle pops and scratches
Led Zeppelin III actually used that lead in as part of the music experience, and the original CD pressing didn't capture it. I've heard CD pressings (even the name remains from vinyl) that do capture it, I don't know when that started.
[−] close04 26d ago

> CD pressings (even the name remains from vinyl)

The name comes from the CDs being manufactured by pressing into a master mold to create the pits. Replicated (mass manufactured) audio CDs are pressed not written with a laser like duplicated ones (CD-R/RW).

[−] notahacker 26d ago
Not to mention the wider context of starting off by opening a beautifully designed record sleeve, and the chances people choosing to listening to vinyl are doing so on a beautifully engineered soundsystem that cost as much as a car when it was released 50 years ago, or a turntable setup that's designed for them to interact with.
[−] hank808 26d ago
Most records these days use CDs as masters, sadly.
[−] ChrisMarshallNY 26d ago
If you pay attention to cats, you figure out they are fuzzy little “difference engines.” They seem to be hyper-tuned to things that change.

For example, if I move a small item in the corner of my room, the next time the cat walks in, he’ll go straight to it, and sniff around.

I have a feeling that cat’s eyes have some kind of “movement sensors,” built in. Maybe things that move look red, and most of the background looks grey.

[−] topham 26d ago
This is true, and illusionary at the same time.

While our precise perception of red may not match, the interplay between colors is such that people perceived them to go together, or clash, etc, in a somewhat consistent fashion.

This means that, over the general population the perception of color is very similar from person to person. Ignoring genetic defects.

[−] phrotoma 26d ago
I have seen Wiggtenstein's language games invoked to explain this "your red isn't my red" possibility, but I've never really been able to follow the reasoning.

Perhaps some philosophically inclined HNer who passes by here can let me know if this is a legit application of his ideas?

[−] 14 26d ago
I have thought about this before as well. Like maybe what I see as red you see as purple but since we have always been taught that what we both see is red to both of us it is red.

I am however leaning more to the belief that typically we all see colors the same. But it is one of those things that could never be proven.

Another interesting thought that comes to mind speaking about color perceptions is I recently read an article or post I honestly don't remember where that discussed what do blind people see like do they just see blackness all the time. According to what I read it claimed that people born blind don't actually see a blackout picture they literally just don't perceive anything. I think for most it would be hard to imagine nothingness but I could accept that as a true fact.

[−] awesome_dude 26d ago
But also - colours don't exist without a name

eg. Before Orange, there was only shades of yellow or reds

[−] jojobas 26d ago

>subjective experience of them is so much more

It's just that our eyes kinda suck and evolution had to make up in buggy software.

[−] huflungdung 26d ago
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[−] waterproof 26d ago
Any day that I learn something new about color is a good day.

Here's my favorite color factoid: There is no such thing as monochromatic pink. You have to make it by combining the two ends of the visible spectrum: somethung reddish and something violet-ish. So that means there is no pink in a rainbow, strictly speaking.

[−] analog31 26d ago
I worked with a brown laser when I was in grad school. It made a couple of brown spots on the wall by accident.
[−] twodave 26d ago
FYI if you get ocular/retinal migraines like me then the exercise in this article might be a bad idea.
[−] greesil 26d ago
Well this explains tripping on acid a little bit
[−] NelsonMinar 25d ago
This video is another good demo: https://www.youtube.com/watch?v=xJLncut79vE
[−] PunchyHamster 26d ago

> Weird stuff will happen, but stay focused on the dot. Blink if you must. It takes one minute and it’s probably best to experience it without extra information i.e. without reading past this sentence.

well that was a waste of fucking time

[−] iqihs 25d ago
i just see cyan on the first one, seems like an exaggeration if anyone is expecting to see 'new' colors
[−] fl4regun 26d ago
very interesting, its quite striking, now I'm even more curious how this compares with the lasers.
[−] junon 26d ago
For those not seeing it or only seeing a little, stare at it for a while then shake your head (or your phone) just a bit.
[−] mapt 26d ago
Is there a single person here interested in photonic computing that wants to explain to the class if there's any "there" there?
[−] spaqin 26d ago
That's most certainly good news (depending on the final cost) for ion trapping quantum computing - the wavelength of the laser they require to trap an ion depends on the molecule chosen, and most setups are expensive, finicky and difficult to calibrate, or sometimes messy if it's a dye laser.
[−] jjmarr 26d ago
I'm excited for new displays where instead of RGB primaries that can only show a triangular subset of possible colours, we have dynamic primaries that can combine to show almost any colour.
[−] krenzo 26d ago
[−] HNisCIS 26d ago
Something to be aware of, the laser safety goggles used by lab workers, pilots, soldiers etc are based on the premise that lasers only occupy extremely specific and narrow parts of the spectrum so by just blocking those little bits, you can get a very effective pair of glasses that doesn't significantly effect visibility. Arbitrary waveform lasers cause problems here.
[−] wizardforhire 26d ago
Just read the article and didn't see anything about building an actual laser… what details the article has (and its scant) its seems they took a fluorescing layer and sandwiched with a color wheel and added the additional wiring and control circuitry… (Obviously more nuanced and interesting physics but still…) cool and practical, but not a diode and definitely not a laser… I could be wrong and would love to be!

… now, if that setup could be drawn out into a fiber laser as cladding with a wide spectrum neural amplifying core (if such a material exists) that could maybe be something idk

[−] xbmcuser 26d ago
Is this the cheaper way to get to extreme uv lithography as from what I understand the largest bottle neck for China has been to get the exact wavelength needed to go small enough?
[−] xphos 26d ago
I don't know to much about photonics but if they ever figure out the boolean algebra and register storage it would be really cool. You have 1 photo cpu core but just use different wavelengths for different threads running in the core. I am sure its way more complex than that but articles like this make you dream about how much we don't know
[−] SEJeff 26d ago
The US Navy has been working on their idea of a holy grail they have deemed the free electron laser[1]

[1] https://boeing.mediaroom.com/2010-03-18-Boeing-Completes-Pre...

[−] wyager 26d ago
The final frontier of display tech (as far as being able to elicit any physiologically possible eye response) is a pair of tunable lasers. You really can't go much farther than that for emissive displays! We're almost saturated (no pun intended) on useful resolution, so I expect color to be the next area of focus.
[−] aftbit 26d ago
Cool, can I get a "proper" yellow diode laser from this? What's the efficiency look like?
[−] anigbrowl 26d ago
I wonder if photonic computing with variable wavelengths essentially gives you a float type in silico.
[−] DarenWatson 26d ago
It’s really fascinating electrons took 60 years to go from chip to a smart device and if photons follow the same thing then we just fired the starting gun. It’s really interesting to see tantala material takes a single laser color in and spits out to a full rainbow.
[−] thayne 25d ago
Does this mean they can create a chip that emits light at a specific frequency they choose? Or the chip can emit a programmable frequency that is controlled "at runtime" so to speak? I wasn't able to figure that out from the article.
[−] spacedoutman 26d ago
My first thought is this will be used as a weapon to bypass protections against specific wavelengths
[−] jcims 26d ago
Can each device vary the color or is it fixed based on how it’s built? Seems the latter?
[−] evo 26d ago
I wonder if this is a nuclear proliferation risk--could it be used for AVLIS/SILEX?
[−] jagged-chisel 26d ago
The "shrinking" circle: I did as asked and clicked the image to see the animation. I saw no shrinking. My eyes did fatigue and I saw the border between the red and green become a blurred gradient.

What should I have experienced?

[−] MeteorMarc 26d ago
Title is misleading. This is about integrated optics that can do "computation" on the frequency of laser input using all kinds of nonlinear optical effects.
[−] himata4113 26d ago
since the light range is so high, technically speaking as the technology improves does that mean we could end up sending petabytes a second over a single fiber optic core?
[−] deepsun 26d ago
Would I finally be able to see bright brown?
[−] foxes 26d ago
From reading assume they mean wavelength of ~ visible light.

I too would like a microwave or gamma laser

[−] analog8374 26d ago
can they do microwave?

if you do the exact right color you can make certain things melt very precisely.

[−] ginko 26d ago
With two of these you should be able to display any color in the CIE colorspace.
[−] cheschire 26d ago
Yes but can it do any color a mantis shrimp would like?

https://theoatmeal.com/comics/mantis_shrimp