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Femto Fairy Lights - Touchable Holograms (i-programmer.info)
mikejuk writes with this story about a Japanese team working on creating touchable holograms. I Programmer reports: "One method of creating a volumetric, i.e. true 3D, display, is to use a high power laser and focus it on a small spot in space. The air in that spot will be heated to the point where it ionizes and glows with a bright blue light. Scan the laser really fast and you can make a full 3D arrangement of glowing points of light — not exactly a hologram but as good as. Of course, the big problem is that you have a lot of energy being focused on small areas and human interaction could be a problem. You might well get burned by the laser if you attempted to touch or interact with the display. The solution is to use a really fast laser, a femtosecond laser, that heats a small spot to a high temperature but only for a very short time. This is much safer because the total energy involved is smaller. This is the reason you can touch sparks without getting burned."
Not yet practical, but maybe this is the technology that one day will give us real working light sabres.
Why project boring fairies, when you can configure it in a straight line and use it for cutting.... butter? Small amounts of butter.
I love waking up to the smell of ozone. I'm sure others share my sentiments.
I saw tech like this ionizing the atmosphere to create holograms years ago. Have they improved on it? Sure, but I can't see it being anything but a diversion from looking for a better path. Even those pools of liquid that use wave forms to create shapes would be better than this. The only thing I can see a use for this tech, of rapid tracking lasers that ionize things, would be in things like a laser defense system, and it could lower the energy cost for such a thing.
Uhh, you wanna be careful about calling Femto a fairy. He kicked Guts's ass using only his mind. And you're no Guts.
Can we think of doing something in light waves, two lasers in beyond visible range, but they interfere with beat frequency in visible range. So the intersection point would have a visible spot. We would only see it if there is dust or something that would scatter the visible light produced there due to interference. And if it is possible to move the interference location by scanning we might be able to project a visible 3D image.
I obviously don't have either the math, or the physics or the electronic skills to do it. In fact I am not even sure it is a viable idea. Wondering if people have tried to use interference between sound waves for such interesting applications?
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
since the technology is likely to be initially exploited for gamers and pron users.
Happiness in intelligent people is the rarest thing I know.
Ernest Hemingway
Will it be possible to mount these things on a shark?
Repeal the 17th Amendment TODAY! Also Please Read http://www.gnu.org/philosophy/right-to-read.html
It's not easy to burn humans, skin is usually covered by a film of moisture and skin is composed of mainly water which has a high specific heat.
Eyes on the other hand are easily blinded by lasers orders of magnitude less energetic that those causing burns. Even reflections from objects can cause temporary or permenant blindness. A technology for hologram displays that blinds it's users is of limited value.
Once the intensity is sufficiently high to ionize air it can easily ionize a denser medium such as water or the skin. Superficially, yet with every sensatory experience one will loose some piece of skin. Femtosecond lasers are used for Lasic at intensties below the ionization threshold of air, still they ablate cornea. Maybe not child safe...
Not yet practical, but maybe this is the technology that one day will give us real working light sabres.
Unlikely. The problem with using lasers for this is that they focus the beam to get the intensity needed to ionize the air and so much of the beam will carry on only slightly attenuated by the plasma. Assuming you had the power requirements to run this intensity continuously (or at least at a far higher repetition rate than todays femto-second lasers) then you could certainly imagine using this to create a tube of plasma like a light sabre but in reality what you have created is a massively powerful laser beam which you have focussed to ionize the nearby air.
This would undoubtedly cut through things but the cutting power would not be limited to the length of the blade and, if you did not bother to focus it, it would extend a great deal further and be harder to detect...but at the cost of looking nowhere near as cool. However I expect that, unlike Hollywood, when it comes to real world weapons effectiveness will outrank the "looking cool" factor by quite a lot. If you really want a lightsabre I think it is far more likely to come from other ways of generating and containing plasma (such as this) rather than using laser-created plasma because in the latter case you might as well just use the laser beam without the plasma.
Can we think of doing something in light waves, two lasers in beyond visible range, but they interfere with beat frequency in visible range.
No. First the beat frequency is the frequency at which the amplitude of the wave oscillates. The frequency of the wave itself is the average of the two waves which make it up. So actually what you would want is one higher frequency and one lower frequency beam of waves so say IR and UV at which point the beat frequency will be too high to see.
The next problem you face is that beats only occur at the precise point where the beams interfere and they are not created and then emitted from that point as a new wave. With sound the ear hears the beats created at the point where the ear is. This would also be the case for light so to create an image you would have to arrange the beams such they interfered on each, individual retina of the people who will see the image with each retina getting a different image to create the 3D effect.
Lastly there are few issues with this in that focussing IR and UV beams onto someone's retina is probably not a good idea from a medical point of view. In addition the frequency would have to be controlled incredibly well controlled to generate the colours and the system would have to track the location of everyone's retina. Lastly, if you overcame all these hurdles, the result would probably be extremely disconcerting because you would possibly be able to see the image whether or not your eyes were open depending on the penetrative power of the radiation used e.g. microwave and X-ray will penetrate the eyelid but again focussing microwaves and X-rays on your eyeball is probably a really bad idea.
I ran into this problem while trying to build a laser lawnmower. You have to boil the water out of the grass before the laser will cut it...
That's actually not the worse problem with a laser lawnmower. If you had tested it on a lawn with a lot of dry grass the resulting grass fire would probably have meant that you would not be here telling us about how it did not work. Still, if you and your house did survive the experience at least you would not need to cut the grass for a while.
So when can I order a light sabre with a beam shaped like Princess Leia?
After the ubiquitous laser warning sign we also need a sign like "do not touch the hologram with the remaining arm" !
Laser Bug Zapper Inches to Market -- the video is from 2010. Didn't realize it had been kicking around that long.