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Author Topic: Can I receive light with an antenna?  (Read 4400 times)

Offline Geezer

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Can I receive light with an antenna?
« on: 14/09/2011 08:06:15 »
Light is just high frequency electromagnetic radiation, right? Why can't I stick an antenna (aerial) on my roof to receive it same as I do with Radio One?


 

Offline CZARCAR

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Can I receive light with an antenna?
« Reply #1 on: 14/09/2011 20:51:21 »
try a glass antena & then use a light amplifier on the other end, like a lightbulb
 

Offline RD

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Can I receive light with an antenna?
« Reply #2 on: 14/09/2011 21:06:15 »
Parabolic dish antennae have been used to receive sound via light ... http://en.wikipedia.org/wiki/Photophone
« Last Edit: 14/09/2011 21:12:14 by RD »
 

Offline yor_on

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Can I receive light with an antenna?
« Reply #3 on: 14/09/2011 22:31:17 »
Don't they use lasers too?
 

Offline Geezer

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Can I receive light with an antenna?
« Reply #4 on: 15/09/2011 03:36:04 »
BTW, for those who have not already guessed, this is a loaded question  :D
 

Offline MikeS

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Can I receive light with an antenna?
« Reply #5 on: 15/09/2011 06:27:23 »
Light, although still photons only covers a limited spectrum of the electro-magnetic frequencies from ultra violet through visible to infra red.  So light is not the same as radio waves which have a much lower frequency.
 

Offline Geezer

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Can I receive light with an antenna?
« Reply #6 on: 15/09/2011 07:38:23 »
Light, although still photons only covers a limited spectrum of the electro-magnetic frequencies from ultra violet through visible to infra red.  So light is not the same as radio waves which have a much lower frequency.

It's all electromagnetic radiation, so what's to prevent me using an antenna to receive light?
 

Offline techmind

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Can I receive light with an antenna?
« Reply #7 on: 15/09/2011 09:13:46 »
Nothing's to stop you using an antenna to receive light, except that as the wavelength of light is very small (ballpark of 450~650 nanometres) you'll need extremely small elements in your antenna. Compare this to a TV aerial which is designed for receiving UHF radiowaves (500~800MHz) of 0.4~0.6metres wavelength...

Of course, you could make an array of such antenna using similar techniques to those used to etch the circuits on silicon chips. However, if you then want to do something useful with the antenna output, you need to make a 'radio' circuit -or at minimum (for a new-technology solar-cell) a rectifier device- which will work at frequencies of 5.5x10^14 Hz. Good luck with that  ;)

If we can solve the rectifier problem, then it seems like it'd be a really cool way to make an efficient solar cell. What I haven't worked out is what the terminal voltage would be for 'full sunlight'. This of course has a crucial bearing on the permissable forward-voltage drop of the rectifier... you could wire a few antenna in series to up the volts, but with the short wavelengths you'd soon run into phasing issues and your antenna could fast become unworkably directional.
« Last Edit: 15/09/2011 09:19:13 by techmind »
 

Offline MikeS

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Can I receive light with an antenna?
« Reply #8 on: 15/09/2011 09:48:47 »
I suppose you could consider the rods and cones of our retina to be a sort of radio aerial in as much as they are tuned to specific frequencies and output an electrical signal.
 

Offline CliffordK

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Can I receive light with an antenna?
« Reply #9 on: 15/09/2011 11:21:54 »
You can stick a solar panel on the roof and receive your light  ;)
 

Offline graham.d

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Can I receive light with an antenna?
« Reply #10 on: 15/09/2011 12:49:32 »
The idea of 1/4 wavelength coatings on glass to minimise reflections and to enhance transmission is analagous to a tuned antenna. It is just a different way to look at it. If you are into RF design it is just equivalent to a matching network.
 

Offline Geezer

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Offline syhprum

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Can I receive light with an antenna?
« Reply #12 on: 15/09/2011 20:44:44 »
If I build a superhetrodyne receiver to operate at visible light frequencies using the best monochomatic lasers available what is the minimum IF bandwidth I can employ assuming efficient AFC.
 

Offline techmind

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Can I receive light with an antenna?
« Reply #13 on: 15/09/2011 21:06:57 »
Here we go!

http://www.amolf.nl/news/detailpage/article/ultrasmall-antenna-controls-light-beam-at-nanoscale//chash/33c4f0c56984c8fe974fc4dfe6b0bfe6/

I did propose something a bit related to this which I demonstrated with 3cm microwaves in an internal company meeting in Holland 3-4 years ago. I/we did draft a patent proposal, but I'm not sure that we carried it through. There's some very interesting technologies and cool applications which can be conceived in this field - but it's hard to see them being commercially viable in the near future...
 

Offline Geezer

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Can I receive light with an antenna?
« Reply #14 on: 15/09/2011 22:05:40 »

I/we did draft a patent proposal, but I'm not sure that we carried it through.


Schtum! Schtum! Not the "P" word. Graham will have one of his turns  ;D
 

Offline imatfaal

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Can I receive light with an antenna?
« Reply #15 on: 16/09/2011 09:50:40 »

I/we did draft a patent proposal, but I'm not sure that we carried it through.


Schtum! Schtum! Not the "P" word. Graham will have one of his turns  ;D

pot kettle kettle pot  :D
 

Offline graham.d

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Can I receive light with an antenna?
« Reply #16 on: 16/09/2011 10:21:31 »
No I won't. I won't even mention the word "patent". Oh,Damn!
 

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Can I receive light with an antenna?
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