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Radio laser or light antenna

Zom-B

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Lasers emit photons and radio antennas emit radio waves.

From what I understand, both photons and radio waves are electromagnetic radiation. Only visible light has a frequency between 400 and 1000 Tera hertz.

So to keep the question short, would it be theoretically possible to make radio wave emitting lasers or light emitting radio antenna?
 

climbak

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radio waves are light. All of the electromagnetic spectrum is light and all of the frequencies are photons and waves. I don't think you can make a radio laser, but there is some astro thing that is sort of like a radio laser. I think it's a maser like thejunkmonger said. I'd look it up now, but I have a quantum final in an hour I should be studying for. I'll try looking it up later though.
 

Ace82

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Oh great, here we go again!   :p This is similar to the "lasers + Magnets" thread.  I go off on one of my theories in that thread, and I get the same feelings here.  My theory is that all energy is related as it all comes from the same source, so the energy in the RF and in the photons can be connected.  As vague as that sounds, yes, I believe it is totally possible for a laser to send a signal (maybe as in laser tag) but I'm not sure how possible it would be to receive it from the light itself, but from sensors.  Using a laser to send RF would have to be accurate to a limited point unlike a wide broadband transmitter.  

EDIT: Not a laser, but through IR LEDs can send numerous signals, such as a TV remote or Pico RC helicopters!

http://science.hq.nasa.gov/kids/imagers/ems/infrared.html
 

Zom-B

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I know very well what LEDs are, and I have been wondering this thing between antennas and LEDs, I just translated it to laser diodes this time. the light and the frequencies do not change. IR LEDs give off light, not radio waves.

I didn't read the lasers + Magnets" thread anymore after the 4th page appeared because it was clogging with stupid, random or fictional ideas or went off topic because they did not know what they were talking about.
 

Ace82

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Zom-B said:
I know very well what LEDs are, and I have been wondering this thing between antennas and LEDs, I just translated it to laser diodes this time. the light and the frequencies do not change. IR LEDs give off light, not radio waves.

I didn't read the lasers + Magnets" thread anymore after the 4th page appeared because it was clogging with stupid, random or fictional ideas or went off topic because they did not know what they were talking about.
That was me! :p Perhaps you didn't know what you were reading! ;D It's very complicated to communicate what makes sense in my head, especially through a forum. Basically, there are many things still officially left in theory, or some things completely phenomenon and left with no valid, logical, satisfactory explanation. “I don’t think outside the box, I tear that shit up!” One day the truth will come out, you’ll see. [smiley=laugh.gif]
 

Switch

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Here's how it is, I'm pretty sure of it. ::)
Like you said "Only visible light has a frequency between 400 and 1000 Tera hertz." OR Radio waves have wavelengths of ~1m  :p They're both photons, only different wavelengths.Different wavelengths act differently in different mediums.Visible light can pass through clear glass, heat (8-14um) and CO[sub]2[/sub] laser beams(10.6um) are stoped by clear glass, radio waves go through concrete and wood and a lot of things.A laser is basicly a coherent light source.I didn't hear about a radio laser(that emits coherent radio waves) but there is such a thing as a "light emiting antenna" and it's pretty common.What does the radio antenna do? It emits a sh!t load of radio waves of a specific frequency in all directions(maybe a parabolic antenna is somewhat collimated but still incoherent). So what's the equivalent thing that emits visible light? A LED! :D(or a light bulb, but lightbulbs emit lots of wavelengths(white light) so the LED is a closer example).As far as I see it you can send a signal with whatever wavelengths you want as long as you have a reciever for it on the other end, wheter it's X-rays or gamma rays or visible light or IR or UV or microwaves or radiowaves or whatever.Maybe a microbolometer could pick up a signal from a low powered CO2 laser , I don't see why not :p


Come to think of it, a radio antena emiting in a lot of frequencies, you know *white noise* is the same as a light bulb that emits *white light*.I guess that's why it's called "white noise" after all...White noise(a lot of frequencies, basicly a lot of radio wavelengths) is compared to white light(a lot of visible light wavelengths that combined, our eyes percieve as white. :D The radio percieves white noise as annoying static.....
 

Zom-B

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You're correct on the noise thing. Did you hear of brown and pink noise? Same origin. You're correct on lots of things. About the antenna thing, I suspected what they emit would be photons, but now what if I didn't put a clean frequency into the antenna but an electrical signal going up and down chaotically? Assume a simple example, a square wave. Would the antenna know that it should emit photons of just those frequencies, in phase, such that they actually sum up to a square wave which was the original signal?

Would it be the instant-Fourier properties which are also observed with lasers, or rather the (quantum) wave front theory which among other things explains mirrors and the precise workings of our ears?
 
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Assume a simple example, a square wave. Would the antenna know that it should emit photons of just those frequencies, in phase, such that they actually sum up to a square wave which was the original signal?
the antenna would emit photons of all wavelengths fed to its vibrator, but not with the same efficiency, though. it would emit most at its design frequency thereby suppressing other harmonics, depending on its design. There are some very flat response wide bandwidth antennae designed primarily for test equipment with fairly constant output impedance over a wide band with varying gain across it.
As of most common antennae, they are narrrow-banded and loading a square wave source the main oscillation of which is at the design freq of the antenna would result in severe impedance mismatch for high order components, which would most likely get reflected back to their source and very little would escape in space. in some instances such standing waves in the feeder line can utterly destroy the source.
 

Switch

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I thought brown noise came from something else ::) I never heard of pink noise.Brown and pink aren't even spectral colours :p

I'm not sure exactly how radios and other stuff that emit radio waves(bluetooth, wifi, etc) work on the inside. :-/ Don't know what you're saying with the square wave.I thought signal was being transmited with radio waves the same way as it is with IR LEDs, it "blinks" very fast in a specific way sending a binary signal across an area until the receiver picks it up , sends it to a processor that analizes and translates it into something usable. :-/
 
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well, there are some mind-boggingly huge antennas for long, middle and shortwave broadcast fed by 500++kW transmitters. These could very well be the only piece of electronic equipment where one could still see operational vacuum tubes even at present day.
 

bob12345

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There is much work underway towards producing a viable light antenna (demand for more efficient solar cells). It's safe to say that this has been on the books for a very long time.
 

Zom-B

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Switch said:
I thought brown noise came from something else ::) I never heard of pink noise.Brown and pink aren't even spectral colours :p
And you imply white is a spectral color?

brown is lots of red, less green and no blue. brown noise is strongest at a low frequency and increasingly weaker with higher frequencies, suppressed 6db/oct (logarithmic)
pink is lots of red and less green and blue. pink noise is strongest at a low frequency and increasingly weaker with higher frequencies, with intensity linearly related to wavelength (1/freq)

Switch said:
I'm not sure exactly how radios and other stuff that emit radio waves(bluetooth, wifi, etc) work on the inside. :-/ Don't know what you're saying with the square wave.I thought signal was being transmited with radio waves the same way as it is with IR LEDs, it "blinks" very fast in a specific way sending a binary signal across an area until the receiver picks it up , sends it to a processor that analizes and translates it into something usable. :-/
radio waves don't blink like a remote controller LED. They operate on carrier waves (like 100MHz for FM radio or 1200KHz for AM radio) and this carrier is slightly perturbed (called: modulated) to transmit analog signals whose highest frequency is a magnitude lower than the carrier wave itself. (this is part of why AM radio sounds crappy, CD audio reaches 22KHz). This modulation can be done by altering the power of the carrier (Amplitude Modulation, AM) or altering the frequency slightly (Frequency Modulation, FM)
 

Switch

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I guess I didn't think that through.But you still can't really have brown light.Brown light would probably be dimmer orange light.

I understand your explanation about how standard radio works.Never knew what AM and FM stood for ;D But CD audio reaches 22kHz in terms of sound waves right? :-/ The way I'm seeing it, you can send an analog signal through a 1200kHz carrier wave to produce 22kHz out of the speaker in the receiver end.I mean, I'm not sure if how radio signal is related to the soundwaves it's being converted in, but at least if you compressed or coded the signal, send it , and decompress it on the other side, you technically could make better sounding AM radio :D
 
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damnit....am i too late?

i have a mathematical analysis test tomorrow so i'll participate later...

but, i dont know if an antenna could emit photons.

and ace-cool: yes, you can send a signal with a laser, with a LED & such. basically the same principle they're applying on the research of laser interconnections inside a CPU.
 




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