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Light and the anti-light
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For years I have been puzzling over light and the possibility of an anti-light wave or maybe a masking frequency. I know light can be affected by physical force like black holes and such and it is also affected by destructive interference My question is: theatrically is it possible to create an anti-light wave or speed up an existing wave to the point it is no longer in the visible spectrum? |
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Re: Light and the anti-light
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by
on 2007-12-20 19:14:48 |
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Photons do not have an antiparticle because they have zero rest mass. Light is not directly effected by black holes or, more generally, by the gravitational field. The gravitational field bends space-time so that when the photon goes in a strait line (for it), it looks curved (to us). Destructive interference is a wave phenomenon, and has nothing to do with antiparticles. It sends chills down my spine when you talk about "speeding up" photons. The speed of light is known to be a universal constant, do not forget that. You can, of course, change the frequency of a light beam by putting shit in its way which will absorb and re-emit the light as new photons. This process, although quite fast in human terms, takes non-zero time, but don't get this confused with "slowing down light" or I'll bite your legs off. The re-emitted photons might have new wave-lengths, calculable by a spectral analysis of the shit what got in their way. You planning to make a cloaking device?? 
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Re: Light and the anti-light
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by SuicidopoliS
on 2007-12-21 03:12:56
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I'd just like to add that "creating anti-light" is in fact amazingly simple... You take exactly the same light as the one you want to annihilate, and you inverse it 180°. Light can be considered as waves, and when you add two waves together with same frequency and amplitude, but 180° phase-shift, they will annihilate each other (e.g. interference). Of course, this is theoretical, and i challenge you to send two inversed light beams (first you'd have to create them) towards each other along exactly the same direction. And about that "speed up [...] no longer in the visible spectrum"... As Gendou said, speeding up photons is BS, but you can change their frequency though, which will indeed possibly make them no longer visible to us. I know there's a research group at the university i study at that focusses on making materials that actually do produce additional harmonics of the incoming light (double frequency, triple frequency,...). Don't ask me about the details though, something to do with non-linear susceptibility blablabla... Way above my head. .oO° Life's THE CURE, the rest are details! °Oo. |
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Re: Light and the anti-light
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by
on 2007-12-21 11:20:11 |
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SuicidopoliS, I accept your challenge!! Start with a monochromatic light source of wavelength λ. Aim this beam into a fiber optic tube. Fork the cable into 2 parts, one having length L and the other L + λ/2. Then, join the two lines together at the far end. The light should annihilate, assuming the brightness out of each line is equal!
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Re: Light and the anti-light
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Na I was thinking more along the lines of an anti light grenade or some ingénues device that allows me to take over the world one of the two Anyway next the masking frequency. Say I broadcast a high level frequency in the light spectrum to amplify the existing light in an area. That would put it out of human sight correct. Now just to figure out how to do it lol But for it to be practical it would need to be emitted from a deferent source. |
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Re: Light and the anti-light
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by EricStillLazy
on 2007-12-21 17:54:52
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Wow is been two years since I've been on this board.. I missed it so. and man Gendou did you get smarter or did I get stupid? who knows. But a friend of mine and I were once talking a couple years ago about something similar to this, we wanted to create a Darkblub, for when you want to sleep during the day, it will absorb light around you, blacking things out.. we never thought about canceling light out, but more of either absorbing it somehow or rather creating electromagnetic interference to block out light from hitting your eyes, but that might cause damage.
WHOOOOOOOOOOO
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Re: Light and the anti-light
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by kudoushinichi
on 2007-12-22 02:55:08
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First of all, 'amplifying' light means increasing the intensity of the light. Which means making the light brighter. Increasing the frequency of the light means we are increasing the energy of the light. Broadcasting high frequency electromagenetic waves is common. You can't see X-rays or Gamma Rays (both have high energy). As for now, I can't see a way where you can absorb surrounding light and re-emit the light at a higher frequency... I think cancelling the surrounding light is a better idea, but still quite impractical...
Shinjitsu wa itsumo hitotsu!
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Re: Light and the anti-light
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by SuicidopoliS
on 2007-12-22 03:50:47 (edited 2007-12-22 03:51:21)
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SuicidopoliS, I accept your challenge!! Start with a monochromatic light source of wavelength λ. Aim this beam into a fiber optic tube. Fork the cable into 2 parts, one having length L and the other L + λ/2. Then, join the two lines together at the far end. The light should annihilate, assuming the brightness out of each line is equal! Although again in theory this is perfectly true of course, i doubt that it would be possible in practice, for the simple reason that splitting an optical cable is something that is never ever done, due to the construction of these type of cables: if you split 'em, they become worthless. You'll always have to use some external tool to split your beam. But then maybe you could use one splitter to split the beam, and one to recombine it... But then you would be facing a number of other problems that would make it highly doubtful that you will be able to make those two beams cancel each other out perfectly... But i guess you're right, using beam splitters you would probably be able to make them cancel out nearly perfectly, but never perfectly, no way... .oO° Life's THE CURE, the rest are details! °Oo. |
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Re: Light and the anti-light
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by
on 2007-12-22 13:44:50 |
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http://www.huihongfiber.com/fiber-optic-coupler.html Looks like the loss is pretty negligible with this device. Non-zero, but negligible in my proposed experiment. I kind of wanna try it, actually. I wonder if I could convince a UCSC professor to go in with me on it...
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Re: Light and the anti-light
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| Yes, but if he wants to cancel out all the light in a room like this it won't work |
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Re: Light and the anti-light
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by EricStillLazy
on 2007-12-23 12:15:17
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I might be missing something here, but what is keeping light from behaving as a particle at the time of destructive interference, thus it not being destructive interference, but just two simlar particles "colliding". I have a hard time thinking of light just "annihilating", I need some conservation in my energy.
WHOOOOOOOOOOO
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Re: Light and the anti-light
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by
on 2007-12-23 13:19:44 |
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Conservation is preserved because photons are electromagnetic waves. Just like waves in a body of water, a wave crest has positive energy and the valley has negative energy. Add them together (have them run into each other, i.e. occupy the same space at the same time), and they cancel out.
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Re: Light and the anti-light
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by EricStillLazy
on 2007-12-23 16:18:12
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Yeah jeez I was missing something! The infamous double-slit experiment shows light under the effect of destructive interference. I have clearly been out the game to long. Now sir I am interested in your fiber optic experiment as well.
WHOOOOOOOOOOO
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