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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 seen some cool case mods with glowing lights, now they could actually serve a propose! Neat.
So, shining a green laser into some goggles: what can go wrong?
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Been saying lasers are cool for ages, but do they listen to me? Nooo...
How efficient is this process? Would it be useful as a general replacement for current refrigeration technology?
It would freeze the water around the shark.
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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.
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.
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.
But what cools the laser?
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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.
Would it be possible to cool CPU chip surfaces by coating them with this glowing material to achieve the same effect?
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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.
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.
On the other hand, Hollywood prop designers finally feel vindicated.
How can I believe you when you tell me what I don't want to hear?
If you actually read the paper (hah), you will see that the mechanism is pretty different (solid state vs gas).
Sorry about hijacking this thread, but nobody seems to have posted the temperatures in a proper scale yet, so here we go:
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 these are handheld pointers. Its all about your collimation, and focus on the desired target. These things are dangerous, and used by kids in third world countries for fun. Oh, btw green lasers emit 3 distinct wavelengths, 808 (almost invisible, therby bypassing your blink aversion), 1064nm (same deal), and 532nm which happens to be the peak wavelength for the cones in your eyeball which appears very intense.
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.