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NIST scientists create 'any wavelength' lasers

nist.gov

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Re: NIST scientists create 'any wavelength' lasers

#111

Post by awesome_dude »

jjk166 wrote: post #57
awesome_dude wrote: post #44

Earlier quoted context omitted.

But also - colours don't exist without a name eg. Before Orange, there was only shades of yellow or reds

The colors most certainly exist without the name. You may have described the fruit as being a weird shade of red, but if someone held up something red and said "so it was this color" you'd say no. Conversely if someone held up something that was actually orange colored, you'd say "yeah it was that color." Similarly, you may have no idea what the name is for the color of a Tangerine, but you know what that color is. Y…

You're actually further away from the truth than you will ever know.

1. Colours do NOT actually exist - they are purely an interpretation by your brain of signals encountered by sensors. Light exists at different frequencies, yes, but what colour is 2.6 GHz? What about light in the gamma spectrum?

2. While the wavelengths were always there, the concept of "Orange" as a distinct category didn't exist for English speakers until the fruit arrived. Before that, it was just "yellow-red" (geoluread) - as has already been mentioned. If you don't have a word for a transition, your brain often fails to categorise it as a distinct entity, effectively "grouping" it with its neighbours. The fruit literally defined the colour for the language.

Finally, just FTR coquelicot is actually a vivid poppy red - it comes from the French name for the flower.

Re: NIST scientists create 'any wavelength' lasers

#112

Post by zh3 »

smallerize wrote: post #98
jjmarr wrote: post #74

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.

That sounds cool but how do you encode the image data?

Just save pixel values as wavelength rather than RGB?

Re: NIST scientists create 'any wavelength' lasers

#113

Post by NL807 »

nabakin wrote: post #59

> 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…

In electric circuits, information is transmitted through the electric field, which itself is close to the speed of light.

Re: NIST scientists create 'any wavelength' lasers

#114

Post by XorNot »

com2kid wrote: post #82
TomatoCo wrote: post #64

Earlier quoted context omitted.

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.

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…

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.

Re: NIST scientists create 'any wavelength' lasers

#115

Post by wdutch »

waterproof wrote: post #106
adzm wrote: post #24

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

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.

When I was young I was taught that pink is a light shade of red. But what kids these days call pink seems to me to be a bright magenta.

Re: NIST scientists create 'any wavelength' lasers

#116

Post by antiterra »

waterproof wrote: post #106
adzm wrote: post #24

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

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.

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 are ‘metameric,’ creating a perceptually matching response in our eyes.

Re: NIST scientists create 'any wavelength' lasers

#117

Post by __MatrixMan__ »

saltcured wrote: post #99
__MatrixMan__ wrote: post #53

Earlier quoted context omitted.

At high energies I think you could point two at a spot in space and get antimatter where the beams cross (also matter, and then an explosion... see the Breit-Wheeler process). We have a hard enough time building shipping-container sized devices that reflect extreme ultraviolet though... so I think a handheld gamma ray laser is off the table for this century.

But, is there any property of that point in space you could measure by how exactly this occurs? I.e. could you make some kind of massive confocal telescope using this effect in place of regular multi-photon fluorescence, to measure a 3D volume of space?

I just thought it would be fun to have a tiny ball of destruction that I could move around arbitrarily. What would I do with it? I dunno... maybe something resembling CNC milling? Etch "hello world" on the inside of a containiner without opening it?

As for building a sensor with it goes... I suppose you could create sources of light very far away without bothering to send an emitter or reflector to that location. Seems like you could use this to build a gravitational wave telescope that was much bigger than the earth.

Probably you could also break some rules regarding line-of-sight communication. If you want to transmit around an inconveniently placed moon you could send an amplitude modulated signal at point on the moon's side, the receiver could send a beam that was nearly at the pair production threshold aimed at the same point. The signal, where it intersected the beam, would take the photon flux over the threshold, repeating your signal from a more advantageous location. Although since we're already invoking godlike technology here... you might as well just use neutrinos to communicate directly through that moon.

Re: NIST scientists create 'any wavelength' lasers

#118

Post by HNisCIS »

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.

Re: NIST scientists create 'any wavelength' lasers

#119

Post by ledoge »

smallerize wrote: post #98
jjmarr wrote: post #74

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.

That sounds cool but how do you encode the image data?

That's the easy part, just use a color space with imaginary primaries (see e.g. ProPhoto RGB), or use one with real primaries that allows for negative values – e.g. Windows uses floating point scRGB for HDR, which is just linear BT.709/sRGB, but negative RGB values can be used to cover the full range of real and imaginary colors.

Re: NIST scientists create 'any wavelength' lasers

#120

Post by Tade0 »

JumpCrisscross wrote: post #33
Tade0 wrote: post #32

Earlier quoted context omitted.

The Mantis Shrimp most likely sees very much like us (or birds, snakes), it's just that its brain is too small to integrate signals from just three types of cones, so it evolved a whole rainbow of cones.

Huh. Anywhere you'd suggest I can read more about this?

https://www.montereybayaquarium.org/stories/meet-the-mantis-...
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