Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

NIST scientists create 'any wavelength' lasers

nist.gov

Post reply on HN
Print view View original

151–160 of 201 posts

Re: NIST scientists create 'any wavelength' lasers

#151

Post by davidmurdoch »

jjk166 wrote: post #94
davidmurdoch wrote: post #79

Earlier quoted context omitted.

I don't think so. Just becoming fluent in multiple languages can result in the perception of more distinct colors. And those fluent in languages that have additional distinct color names can differentiate subtle differences in the shades of colors that non-speakers cannot even differentiate. Color is less about seeing what is actually out there and more about how our brain interprets colors to create "meaning".

> And those fluent in languages that have additional distinct color names can differentiate subtle differences in the shades of colors that non-speakers cannot even differentiate. The ability to label more colors is not the ability to perceive more colors. The ability of your cone cells to recognize a difference in color between two samples is unaffected by language.

Your cone cells do not perceive anything whatsoever. Your brain does that part. Those who grew up with words (meaning) assigned to subtle variations in colors can tell those colors apart without a reference to compare it to better than, and much faster than those who haven't grown up with learning the distinction.

We know this to be obvious of sounds, musicians who can tell if a note is slightly out of tune when others who haven't learned how can't, or taste/smell: wine connoisseurs who can tell very similar wines apart that all taste the same to me.

You're not thinking in photons. Your brain is making up meaning from the stimulation your eye received from photons. The perceiving part is learned.

Re: NIST scientists create 'any wavelength' lasers

#152

Post by close04 »

dotancohen wrote: post #127
XorNot wrote: post #114

Earlier quoted context omitted.

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.

> 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.

> 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).

Re: NIST scientists create 'any wavelength' lasers

#153

Post by patapong »

sgc wrote: post #76
jcul wrote: post #42

Earlier quoted context omitted.

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.

> 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. 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…

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...

Re: NIST scientists create 'any wavelength' lasers

#154

Post by sysguest »

sgc wrote: post #76
jcul wrote: post #42

Earlier quoted context omitted.

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.

> 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. 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…

> 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)

Re: NIST scientists create 'any wavelength' lasers

#155

Post by jmusall »

criticalfault wrote: post #17
topspin wrote: post #14

Earlier quoted context omitted.

There is there there... The substance is they've created a way to fabricate a device that can make the optical frequencies they wish. That is useful: it means a designer isn't limited to frequencies that are economic to generate with existing techniques, which is a constraint that lasers currently struggle with: low cost, compact, efficient laser sources (the kind that fit on a chip, and are fabricated by cost effect…

I wonder if this could also work for (e)uv

Probably not because EUV gets absorbed incredibly quickly by anything other than vacuum. This is why it is created in low density gas, thin liquid or solid samples (high harmonic generation) or electron clouds (free electron laser).

Re: NIST scientists create 'any wavelength' lasers

#156

Post by close04 »

ChrisMarshallNY wrote: post #150
da_chicken wrote: post #55

Earlier quoted context omitted.

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.

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 lo…

Even human eyes have some areas, outside the fovea centralis, that are very sensitive to motion even in low light. In the dark you will see motion out of the corner of your eye but you will only see pitch black if you stare in that direction.

The other part you mention is more interesting, I noticed it too. That must be a mechanism in the brain rather than the eye. It’s like the cat keeps a “snapshot” of that place to compare against next time it comes by. This might also explain why they take the same route all the time, maybe it gives them a good reference against the old snapshots.

Re: NIST scientists create 'any wavelength' lasers

#157

Post by antiterra »

matthewmacleod wrote: post #129
antiterra wrote: post #116

Earlier quoted context omitted.

This is conflating two kinds of pink. The pink made from combining ends of the spectrum is most commonly termed ‘hot pink.’ The other, very often just ‘pink,’ is predominantly a light red. A quick and sloppy way to describe this is a light grey with a raised red component. Also, you can make hot pink without needing to use spectral violet (the ‘end’ of the spectrum) since there are combinations of blue and red that a…

The other, very often just ‘pink,’ is predominantly a light red. A quick and sloppy way to describe this is a light grey with a raised red component. While that’s true, it’s also still not monochromatic in the electromagnetic sense.

Absolutely, I had that in my draft but chopped it out along with a digression into black body radiation.

Re: NIST scientists create 'any wavelength' lasers

#158

Post by mapt »

robocat wrote: post #92
nine_k wrote: post #21

Earlier quoted context omitted.

Immediately: * You can pack many more different colors into fiber optic communication lines. Every color carries a few tens of GHz in modulation, but the carrier light is in hundreds of THz; there's a ton of bandwidth not used between readily available colors. * You can likely do interesting molecular chemistry by precisely adjusting laser light to the energy levels of particular bonds / electrons. * Maybe you can pr…

> precisely adjusting laser light to the energy levels of particular bonds / electrons. However, the article is talking about discrete wavelengths. The device gives you a choice between a bunch of different fixed wavelengths. It isn't actually tunable to specific frequencies. Disclaimer: skim read article plus I know very little about the topic

We can tune them slightly with differences in temperature if I recall correctly, but there are limited uses for a few nanometers up or down in wavelength. If there's now a versatile multi wavelength generator for numerous specific discrete frequencies, you may be able to just cool it down to access nearby bands.

Re: NIST scientists create 'any wavelength' lasers

#159

Post by mapt »

nine_k wrote: post #21
mapt wrote: post #2

Is there a single person here interested in photonic computing that wants to explain to the class if there's any "there" there?

Immediately: * You can pack many more different colors into fiber optic communication lines. Every color carries a few tens of GHz in modulation, but the carrier light is in hundreds of THz; there's a ton of bandwidth not used between readily available colors. * You can likely do interesting molecular chemistry by precisely adjusting laser light to the energy levels of particular bonds / electrons. * Maybe you can pr…

Didn't we already invent much of this with wavelength division multiplexing and optical routing switches, the invention that pierced the tech bubble by quite suddenly increasing bandwidth of in-place fiber pipes by ~100x during a large buildout?

(I am not an expert, but this is the narrative I've heard; I may not be using the right words)

Post reply on HN