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Mastering Light
thyristor writes "'Researchers at MIT document the ultimate control over light: a way to shift the frequency of light beams to any desired colour, with near 100 per cent efficiency. This technology could revolutionise a range of fields, from turning heat into light, or even into prized terahertz rays - which hold great promise for medical imaging. It could also make it possible to focus a wide range of frequencies into a narrow band, make devices such as light bulbs and solar cells more efficient, and help to keep optical telecommunications networks moving.' These are probably the most exciting results in photonics in the last decade."
So, with this, could we look at Ultraviolet radiation with the naked eye (through a converter)? That would be cool! :).
Being able to see infrared radiation would help a lot for playing hide and seek in the dark
How long until we have lightsabers?
/. had an article about lazer rifers for the U.S. Military, would they be able to actually curve the beams around objects and such?
But honestly, do they have the ability to actually shift the light, almost like a curve effect to the beam. Cause I know not too long ago
Reading the article it seems that the light frequency is altered for only a short time, the time during which the shock wave passes through the crystal. So I don't think it's some magic filter where you can shine a green light in one end and get red light out the other. In the long term the number of peaks and troughs you put in at one end must equal the number seen at the other, so you can't consistently alter the frequency of a light beam in this way.
IANAP, anyone care to provide more detail than seen in the article? Will the planned demonstration of the work give results observable to the human eye?
-- Ed Avis ed@membled.com
Ok, now, can we control the "shift" from software? which a real explaination for how StarTrek does those "lets generate a xMhz pulse" sorts of things... sending hailing signals over arbitrary frequencies. (like if you had an array of these devices tuned to different freq.). Also, (boy the nerd in me loves this), it generates ideas for reception.. tuning all sorts of frequencies into a standard freq (like for SETI searches....)... wow, neat idea folks.
meh
If they could shift heat waves -> light waves, then absorb those with photovoltaic cells, we could harness lots of wasted energy. Almost everything generates wasted heat energy, and isn't heat energy basically the same thing as light waves, just at a different frequency?
So, does this mean we can make ourselves invisible? If we would make a suit of frequency shifters we could make the visible light turn into radio waves, let them pass through the body, and then change them back into visible light. Of course, it would require huge amounts of energy aswell as precision, so it probablly won't happen anytime soon. Interesting thought, though.
An optical router. An incredible array of lenses and lasers and "light controllers". It would take up an entire room and be a dust free vacuum. It would be so awesome, not to mention cool looking.
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Well, with such a frequency translator, we can all imagine all the goodies and baddies that can be made with it. One of them is a cloaking devices, efficient power sources, phase weapons...
Imagine changing harmless light from light bulbs into a focused gamma rays or worse !
the light frequency is altered for only a short time
...
... metastable. :-) It doesn't matter, the point is that the wavefronts are recreated continuously, and with sound that doesn't seem all that hard.
The "short time" doesn't really matter, and furthermore looking at a "light beam" as an end-to-end continuous sine wave that you stretch and compress doesn't really help here
Photons last forever (well, until absorbed etc). Once one has escaped from the reflection zone between shockwave fronts, it doesn't wither and die, it's permanently changed to do our beckoning. The fact that its "home of origin" has since moved on isn't really of any further concern. (And notice the difference in velocities between light and shock wavefronts, ie. hare and tortoise, so from the photon's point of view the generator is pretty static.)
Complaining that the shockwave fronts are transitory is like complaining that the metastable states in lasers are, er
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
Having the ultimate sunglasses... have it shift Ultra-violet to a more visible frequency...
Or perhaps even infrared/heat?
Cool glasses that make you see in the dark? (military applications?)
Whee!
"We ought to be able to do things that have never been possible before," Joannopoulos. While this is true, its application remains to be seen. I'll wait with held breath for their publication.
On the same note, I wounder wheather this is just the begining of similar earth shattering (whell, light bending in this case) breakthroughs in other fields due to bringing ideas of two different fields together. Most optics people I know would never even consider bringing sound into the picture.
My prediction: new sight and smell techniques will revolutionze the way scientists do research by allowing for instantaneous point density determinations in complex 3-d flows. (Extremely useful!) This will happen when this advacment using sound to modify crystal properties is coupled with a device that picks up minute particle changes over a surface (smell) and correlates the two internally.
-=fshalor
Uhm, it wouldn't mess up anything. A 1280*1024 colourdisplay is essentially a 3840*1024 "monochrome"-display (each R,G,B being separate elements). If you wouldn't need separate elements, you'd have a true 3840*1024 colour display, which would be vastly superiour to sub pixel rendering .. :)
it's in my head
Ummm... How would you get white (red, green, and blue at the same time)? I suppose that you COULD rapidly switch between multiple frequencies to get a simulated white, but the article did not explain how much control you could get over the process... Perhaps a single crystal would only provide a fixed shift (red->blue), and if you wanted red->green, you use a different crystal.
Also, each pixel would need its own crystal and "hammer" (probably a piezo element). This would probably be even more expensive than current flat-screen televisions.
Just one more note -- if you have little crystals being hit at 60Hz (assuming a progressive scan display), that sucker would humm like crazy!
"-1 Troll" is the apparently the same as "-1 I disagree with you."
how cool - finally we can have computers full of flashing lights Just like in the movies...
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Anyway, because the redshift comes from the space itself expanding, it's proportional (I think it's a linear effect, I don't remember too well) to the distance between you and the object under observation. Yes, there is some Doppler style redshift, but that is not what's generally meant when an astronomer says "redshift". Also, cosmologists use redshift (z) as their primary variable in many equations. Most cosmologists measure distance in redshift, instead of cgs or mks length units.
Down with Saudi Arabia!!!
By taking sunlight and turning it into microwave radiation, you could get far greater efficiency out of the generation of electricity.
This would make microwave beaming satellites highly efficient. The current idea was to have huge solar arrays which would of course alter the look of the sky during the day or night. These would convert some of the light into energy and probably reflect the rest of lose it as heat. The elctricity generated would produce a microwave signal which would be beamed down to a ground station and converted back into electricity. With this new technology, they could have far smaller arrays which convert the light directly into microwaves and transmit, eliminating the overhead of going from light->electricity->microwaves->electrici ty on the ground.
Instead you would have light->microwaves->electricity on the ground.
And you wouldn't need a mile long array of cells to collect enough power to make it worthwhile because your effeciency would be extremely high.
--Won't that be grand? Computers and the programs will start thinking and the people will stop. - Dr. Walter Gibbs
Does this mean we'll finally be able to get X-Ray specs?
If I seem short sighted, it is because I stand on the shoulders of midgets
"Huh, that's not supposed to happen..."
WARNING: there is a trojan on your
IANAP[hysicist], and so I have some questions about this process.
What I know:
So, when light is converted to a higher frequency (shorter wavelength) where does the necessary energy come from? The shockwave? What about when it is converted to a lower frequency (longer wavelength)? Where does the excess energy go? If the conversion really is 100% efficient (I'm a bit skeptical of that claim), then just imagine the solar panels we could have; sucking up all the UV raining down on us and emitting a soft red glow.
Fascinating stuff. I've got to study more optics and electromagnetic physics.
Does this remind anyone else of the Ledbetter effect that Heinlein described in his "Sixth Column" novella?
Seems like there was another Heinlein story that used a light wavelength shifter as an energy resource - one that ultimately powered moving sidewalks...anyone remember the title of that story?
Of course I haven't seen their simulations, but where does this "near 100%" figure come from? The first test is going to use a bullet (!) and they are projecting that a more refined version will use sound waves. Something has to produce those sound waves, and the waves have to be powerful enough to alter the characteristics of the crystal.
Now I understand that in theory a light wave at a given frequency could transform to a higher frequency and lower intensity (conservation of energy is not violated), but that's analogous to changing the gear ratio on a motor. A gear system always introduces some loss.
Now, given that any practical implementation of this will require a wave generator that's likely to make some noise, I don't see it ending up in lightbulbs or solar cells. If you want to get more light to a solar cell, focusing a mirror on it and keeping it cool is probably more practical.
However, the medical imaging tech sounds like a great application. Noise from medical scanners is an acceptable part of that experience.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
The 'near-100% efficiency' doesn't mean that the process is energy-free, just that the light coming out is almost as intense as the light coming in. Ordinary filters don't convert anything, they just block out what you don't want. If only 10% of the emitted light is of a frequency you want, then 90% is lost by using a filter. This process actually converts the incoming light into the outgoing, so any losses are due to imperfections in the system.
Dyolf Knip