Researchers Use Lasers For Cooling

MatthewVD writes "Infrared cameras on satellites and night vision goggles could soon use lasers to cool their components. According to the study published in Nature, researchers in Singapore were able to cool the semiconductor cadmium sulfide from 62 degrees fahrenheit to -9 degrees by focusing a green laser on it and making it fluoresce and lose energy as light. Since they require neither gas nor moving parts, they can be more compact, free from vibration and not prone to mechanical failure."

I may finally install lights in my PC

[jackb_guppy]

I seen some cool case mods with glowing lights, now they could actually serve a propose! Neat.

Wow, Singapore !!

[Taco Cowboy]

Singapore is a tiny island nation, with a tiny population of 4 million citizens (the actually number of people living on that island is 5+ millions, but with close to 2 millions being non-citizens).

I guess congratulations are in order for that tiny nation for funding these type of advance research !

Perhaps t'is another indication of the shift from the West to the East,

Re:

[justthinkit]

Careful on the temperature of that inferno. [answers.com]

Re:

[bitingduck]

I've known more than a few USians who left and went to Singapore because the funding situation is a lot less hassle-- no more proposals to underfunded agencies with low hit rates for small pots of money. Singapore sets them up with a nice lab and stable funding so they can do the things they went into science for in the first place. It doesn't sound bad, but I wouldn't really want to live in Singapore.

temperature in celsius

[Anonymous Coward]

Sorry about hijacking this thread, but nobody seems to have posted the temperatures in a proper scale yet, so here we go:

Researchers in Singapore were able to cool the semiconductor cadmium sulfide from 17 degrees Celsius to -23 degrees

Re:

[Cmdrm]

A proper scale? Shouldn't it be in Kalvin then?

Researchers in Singapore were able to cool the semiconductor cadmium sulfide from 290 degrees Kalvin to 250 degrees Kalvin

Re:

[Anonymous Coward]

A proper scale? Shouldn't it be in Kalvin then?

Researchers in Singapore were able to cool the semiconductor cadmium sulfide from 290 Kelvin to 250 Kelvin

Fixed your fix.

Re:

[CubicZirconia]

A proper scale? Shouldn't it be in Kalvin then?

Shouldn't it be in Kleins?

Re:

[Cmdrm]

A proper scale? Shouldn't it be in Kelvin then?

Researchers in Singapore were able to cool the semiconductor cadmium sulfide from 290 degrees Kelvin to 250 degrees Kelvin

Fixed it for myself

Re:

[Cmdrm]

A proper scale? Shouldn't it be in Kelvin then?

Researchers in Singapore were able to cool the semiconductor cadmium sulfide from 290 Kelvin to 250 Kelvin

Fixed it for myself

Fcuk, I shouldn't comment after flying (Kelvin are absolute units)

Re:temperature in celsius

[ChrisMaple]

No, it should be in Hobbes.

Re:

[arc86]

If you want to turn 40 watts of heat into blue light, I'm figuring that's something like 5000 lumens you're creating according to the luminosity function. That's a conference room projector worth of light. Then you have to figure the laser power required to get that much heat out, which according to the article's 2 percent efficiency estimate would be...a lot. I don't know how "cooling efficiency" is defined. Ideally you'd move the emission to infrared, but that would be disastrous for your night vision

Re:

[realityimpaired]

Rapid pulsing lasers (femtolasers) can drastically increase the wattage without actually increasing the number of joules drawn. Without having read the article (this is /. after all), it seems to me that using a pulsed laser would actually be better for this kind of application, because the medium being cooled needs time to actually let off the photons being generated.

That being said, yes, I imagine that active cooling methods are probably significantly more energy efficient, at least for the moment. A pelt

Yeap, a bright idea

[c0lo]

So, shining a green laser into some goggles: what can go wrong?

Re:Yeap, a bright idea

[ackthpt]

Ze goggles, zey do NUTHINK!

I see nothing wrong with the goggles... I see NOTHING! AAAAAHHHHHH

Re:

[rally2xs]

Are they heavy? Yes? Well then they're expensive. Put 'em back.

Re:

[BlackSnake112]

Do not look directly into the laser with remaining good eye.

Pff

[Anonymous Coward]

Been saying lasers are cool for ages, but do they listen to me? Nooo...

Re:Pff

[ackthpt]

Been saying lasers are cool for ages, but do they listen to me? Nooo...

So I'm out with the astronomy club with all our cool glass and tubes and stuff and have people looking at Jupiter, Saturn, Mars, M-13, fun stuff like that there. Someone asks, "Which star is Sirius?" I pull out my laser pointer and show them. Little kid says, "Whoa! That's COOL! Mom! Buy me one!"

I tell the mother, "No, do not buy him one. Laser is not toy. Can blind himself or a friend with it. Under no circumstances should you buy him a laser. Buy him a UV flashlight to look at centipedes or something."

Lasers are cool, but only for grown up kids.

Re:Pff

[GumphMaster]

These pointer lasers are controlled items in many places because, aside from the obvious general hazard, morons deliberately point them at aircraft cockpits. Only occasionally do the fools get identified [abc.net.au] but it warms the cockles of my heart when they do: I am an amateur astronomer and have also been involved in the airborne end of this stupidity.

Re:

[deimtee]

A moron indeed. You need to be a malicious arsehole to point one at a plane, but how dumb do you have to be to point it at a Police helicopter!

Re:

[Genda]

It happens, and the answer is flat line on he EEG brain dead.

Re:Pfft

[coldproduct]

Agreed, having worked with a lab that certifies products sold in the US (21 cfr) and internationally (60825-1 and -2), lasers have gotten more powerful and compact than most folks realize. Class 4 lasers are easily integrated into the handheld green pointers that most of us have seen. What isnt realized is that the 150mw pointers that will blind you like a thief in the night. I have posted blue 445nm and green 532nm lasers to youtube that I have made burning through objects in close proximity, remember t

Re:

[mat8913]

I liked lasers before they were cool.

Efficiency

[kevink707]

How efficient is this process? Would it be useful as a general replacement for current refrigeration technology?

Re:

[MichaelSmith]

I think it only cools things which fluoresce.

Re:

[phozz bare]

That shouldn't be an obstacle, as current refrigeration technology doesn't directly cool the air in your fridge/home/office either. It would be possible to cool some object using the laser then use the low temperature of the now cold object to cool the surrounding air. However as long as the efficiency is indeed 1.2-2% as mentioned in an adjacent comment this is no replacement for current A/C tech.

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[skids]

However as long as the efficiency is indeed 1.2-2% as mentioned in an adjacent comment this is no replacement for current A/C tech.

I guess that depends on how efficiently the fluoresced light (and refracted laser light) can be converted back into electricity.

Re:

[Anonymous Coward]

How efficient is this process? Would it be useful as a general replacement for current refrigeration technology?

Depends on the temperature you start cooling at but between 1.2 and 2% so dont expect to see it in a fridge any time soon.

Re:

[dywolf]

Possibly not too efficient. But, this process has a huge advantage over current methods that is completely ignored by the article and many slashdotters so far: it would work in a vacuum. And when you're the only viable method in town for a certain niche, efficiency doesnt matter so much.

Re:

[DrStoooopid]

Yeah, but when you close the door, the light will go on!

That wont work..

[Brad1138]

It would freeze the water around the shark.

Rubidium

[DarwinSurvivor]

This has been used to cool rubidium to near 0K in labs for a while. Takes some work (the laser needs to be *perfect*), but I've seen the setup myself at a previous employ at a local University.

Re:Rubidium

[Noughmad]

No, this is different. What you describe is called Doppler cooling [wikipedia.org] and is basically "slowing down" the atoms/ions.

TFA, on the other hand, talks about using a laser to cause fluorescence in the material. It's a completely different principle.

Re:

[DarwinSurvivor]

Yes, your description is just how it was explained to me. I wasn't sure if the one in the article used a similar process. I do remember the rubidium "glowing" so I thought it might be the same.

Re:

[Anonymous Coward]

The cool in Doppler cooling comes from absorbing the photon which changes the kinetic energy of the atom, then fluorescence that does not contribute back to the heating. Here, it is dependent on the semiconductor band structure, and involves absorbing the photon, then a release of another photon and a phonon to cancel out lattice vibrations.

Re:

[wiredlogic]

The laser shines inside onto the back of the sensor.

Might work ?

[perpenso]

The primary purpose of Night Vision goggles is to see clearly in the dark in those times where you can't/won't use a torch. So, in times where you may not want to be seen yourself. How is it helpful to have the goggles shine with green laser light to cool them off in this situation?

Presumably the system would be completely self contained. Neither the laser nor the fluorescing being visible. Maybe we can think of the fluorescing as a mechanism to conduct heat from the electronic components to the case of the NVG. Of course that would heat up the NVG case but perhaps it is not emitting in the iR anymore than the person's face underneath it. More info is needed.

Re:Might work ?

[unrtst]

Presumably the system would be completely self contained. Neither the laser nor the fluorescing being visible. Maybe we can think of the fluorescing as a mechanism to conduct heat from the electronic components to the case of the NVG. Of course that would heat up the NVG case but perhaps it is not emitting in the iR anymore than the person's face underneath it. More info is needed.

I've seen multiple posts like this one, and they all seem to be missing a huge point (maybe I'm getting trolled? ... or maybe I'm completely wrong).

From the article (sorry, I read it):
"...starting from 290 kelvin. We use a pump laser with a wavelength of 514 nanometres, and obtain an estimated cooling efficiency of about 1.3 per cent and an estimated cooling power of 180 microwatts."

Where the hell is all the heat going if you stick this thing inside some goggles with the direct purpose of cooling something inside said goggles? That question has nothing to do with the above quote... it's there to drive it home - look at how inefficient this process is!?! I'm sure it's extremely useful and interesting for a great many cases, but I don't see (pun) how this is good for night vision goggles.

I keep picturing a guy on a sailboat blowing really hard on his sail.

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[perpenso]

... How is it helpful to have the goggles shine with green laser light to cool them off in this situation?

Presumably the system would be completely self contained. Neither the laser nor the fluorescing being visible. Maybe we can think of the fluorescing as a mechanism to conduct heat from the electronic components to the case of the NVG. Of course that would heat up the NVG case but perhaps it is not emitting in the iR anymore than the person's face underneath it. More info is needed.

I've seen multiple posts like this one, and they all seem to be missing a huge point (maybe I'm getting trolled? ... look at how inefficient this process is!?! I'm sure it's extremely useful and interesting for a great many cases, but I don't see (pun) how this is good for night vision goggles.

I'm not arguing that it would work or even be practical. There must be easier ways to conduct heat, methods that don't add to battery usage. I'm just pointing out that the laser and the fluorescence are internal to the unit, and that only key electronic components need to be cooled not the entire unit. :-)

Re:

[darkfeline]

There's no law of preservation of heat, only preservation of energy. Presumably, part of the heat energy is transformed into light, and part of it is stored into the reactant products. Think of those portable heat packs. "If the pack itself is at room temperature, where does the heat come from?" Also, heat != temperature.

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[sFurbo]

It is a "new" way to move heat. In night vision goggles, it could move heat from the sensor to the casing, as only the sensor (and perhaps the optics) must be cold. However, I would imagine a Peltier element being more efficient, and that this mostly makes sense where a) You have no heat sink (mostly in space, I guess) or b) The cooling devices is not in direct contact with what is being cooled (the technique is already used in this way to cool gasses for making Bose Einstein condensates, where the thing be

Re:

[unrtst]

Things in space and really cold stuff makes perfect sense. Both articles even point to that for the most part.
The night vision thing is only mentioned in the dumbed down txchnologist piece, and only once, and via a small quote from someone that wasn't even involved in the project:

“The big potential users of this cooling technology are night-vision goggles, and infrared cameras on satellites, where weight is very important and you would not want the motors and pumps and vibrations that come with regular coolers if you can,” says Richard Epstein, a University of New Mexico physicist and CEO at technology startup ThermoDynamic Films, who did not take part in this research.

I'd love to know the rest of the context for that comment, because it seems absolutely crazy to me that night-vision goggles and infrared cameras on satellites are _THE_ big potential users of one given cooling technology... those

Re:

[Jeng]

I was picturing the display of the goggles being the light output from the cooling, so the display would be endothermic instead of exothermic.

Re:Defeats the purpose

[aXis100]

It's only the sensor that needs to be cooled below ambient, other parts can use traditional methods. So, you make the back side of the sensor flouresce, capture that light in a chamber where it is converted back to heat, then dissipate that heat through regular air cooled heatsinks.

In the end it's just shifting the heat whilst working against a thermal gradient - same as a refridgerative system, but without moving parts.

Re:

[pushing-robot]

On the other hand, Hollywood prop designers finally feel vindicated.

Re:

[account_deleted]

Comment removed based on user account deletion

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[GameboyRMH]

BECs means Bike Engined Cars to me.

Re:

[cusco]

Bose-Einstein Condensate seemed obvious to me, but what the frack is a 'Bike Engined Car'??? Pedal-powered? Or 'bike' as in 'motorbike'?

Re:

[GameboyRMH]

A car with a motorbike engine.

Re:

[Anonymous Coward]

If you actually read the paper (hah), you will see that the mechanism is pretty different (solid state vs gas).

Use SI units for reporting science

[Anonymous Coward]

The scientists used SI units all the way through in their paper (Kelvin for temperature), and they would have been laughed out of court and certainly not published in Nature if they'd done otherwise.

Why does Slashdot even accept a submission in Fahrenheit when the subject is science? Most nerds understand SI units, and most of the planet is metric. How about trying to be a bit educational for the few that don't? Quote both if you're trying to be helpful, with the SI units as primary for science reporting and imperial equivalents only in brackets.

Re:

[ColdWetDog]

Why does Slashdot even accept a submission in Fahrenheit when the subject is science?

Because you can't do car analogies in SI units. It just doesn't work.

Metric is fine for car analogies ...

[perpenso]

Why does Slashdot even accept a submission in Fahrenheit when the subject is science?

Because you can't do car analogies in SI units. It just doesn't work.

Metric is fine for car analogies. Contemporary cars need metric tools, even US domestics.

Re:

[bar-agent]

Why does Slashdot even accept a submission in Fahrenheit when the subject is science?

Because you can't do car analogies in SI units. It just doesn't work.

Yeah. It's like...talking about the miles per gallon of an electric car.

Because retro is cool

[davidwr]

In tech circles, english units are the Steampunk of measurements.

Re:

[tsa]

This. But the US probably thinks that together with Lyneria and Muanmar they are the only developed countries on the planet.

Re:

[tsa]

Damn virtual keyboards. Lyberia and Myanmar!

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[tepples]

Damn virtual keyboards. Lyberia and Myanmar!

So would you agree that even a laser-projected keyboard [slashdot.org] isn't cool for typing?

Re:

[K. S. Kyosuke]

Damn virtual keyboards. Lyberia and Myanmar!

Let me type "Liberia" for you on my entirely non-virtual keyboard. :-)

Re:

[tsa]

Damn me! :)

Re:

[Sockatume]

If it was in Celsius or Kelvin US readers wouldn't know whether to wear a coat or shorts when they went to visit the laser.

Re:

[semi-extrinsic]

Reply to undo wrong mod.

Re:

[gef7]

Information which passes via US news redistribution streams is obviously mangled... business as usual!

Re:

[rdnetto]

Thanks, but we're here for a science lesson, not a history one.

Cool!

[tsa]

But what cools the laser?

Re:

[perpenso]

But what cools the laser?

The heat sink with external cooling fins (maybe a low RPM fan ?) that the NVG electronics used to be connect to. :-)

Re:

[gman003]

More lasers.

Re:Cool!

[Nationless]

Another laser, duh.

Re:Cool!

[Anonymous Coward]

It's lasers all the way down.

Re:

[Jah-Wren Ryel]

But what cools the laser?

The frickin' sharks attached to the lasers!

Awesome

[sidevans]

I've been looking for new ways to keep my flux capacitor cool.

Let me get this straight...

[AJWM]

... you make the light sensor more efficient by making it fluoresce?

Um, right. Good luck with that.

Sundiver.

[bejiitas_wrath]

The novel Sundiver [wikipedia.org] by David Brin did this; they used a powerful laser to suck heat out of the Sundiver craft within the atmosphere of the Sun.

Peltier

[gringer]

How does this compare with peltier cooling? Is there some obvious reason (e.g. no airflow) why peltier won't work in space?

Re:

[GameboyRMH]

I think peltier would be inefficient in space...you need power to run it, and you could add heat exchangers to a passive cooling system instead of the solar panels needed to run the peltier cooler.

Re:

[bitingduck]

Depends on the desired temperature, where you are in space, and where you have to move the heat from and to, and how much heat you have to move. Peltier coolers are indeed used in space, along with many other cooling technologies. All active coolers in space get tied to passive radiators to dump the waste heat.

A perfect CPU fan replacement?

[Twinbee]

Would it be possible to cool CPU chip surfaces by coating them with this glowing material to achieve the same effect?

Laser cooling is handy, but requires precision

[drwho]

Handy for things like uranium isotope separation, and also for creating things like Bosenovas. The problem is, that the process is very sensitive to the frequency of the laser. If these guys have found a way to reliably, inexpensively create the right frequency of light to cool anything...then that substance can act as a heat sink to cool other substance. This could open a whole exciting new era of science and technology. But I won't hold my breathe, the proof is in the pudding, etc.

Re:

[cusco]

When I first read your post I was wondering how a laser could create Brazilian music (bossa nova), but I guess an exploding Bose-Einstein Condensate is worth checking out too.

Sundive in 5...4...3...2...1

[Somebody Is Using My]

We have our refrigerator laser, now all we need is a stasis generator, to "control the flow of tune and space through the body of the Sunship, so that the violent tossing of the chromosphere would seem a gentle rocking to those inside." And I'm sure we'll have that any day now.

Yup.

Any.
Day.
Now.

Sharks don't cook their meat

[locopuyo]

Finally they can keep their kills from rotting so they can eat them later.

Now we can have a really cool shark with a laser

[q.kontinuum]

No further text

Saucer Lights explained

[ayahner]

That must be why the mother ship has all those lights. Cooling lasers. The overlords see in the heat spectrum (or not at all) and so never expected us to detect them. Blaart: It's like the huuuman is looking right at ussss. Pleaotard: Not possible, Overlord Blaartumus. We have the cooling lasers working overtime.

Re:

[GameboyRMH]

I lol'd XD

Re:

[ackthpt]

In Soviet Russia, laser puts in the cooler you!

Re:

[ledow]

Well, put some of that semiconductor underneath the base plate, aim a 800W laser at it contained inside the device - depending on the speed the material loses heat at, it might be possible to make a "microwave freezer" that freezes (or at least cools) things in seconds.

Probably pie-in-the-sky because of some physical limit (i.e. it might take hours to cool no matter how much power you aim at it), but the "microwave freezer" has been an April Fool "hoax" on at least one BBC science programme (Tomorrow's Worl

Re:

[ledow]

1.2% efficient isn't bad for the first go at getting this effect with semiconductors though.

Hell, I bet early solar panels weren't even that efficient, and they are all over the world now.

You would need to get to about 50% efficiency to make them useful, though, but with no-moving parts and all the other advantages, probably even less than that would make them have practical application.

Re:

[IndustrialComplex]

I'm not sure I understand, what is retarded about the units? Has their velocity been reduced?