What will happen when we send data in the visible light frequency?
If so how will it look as it is carrying a data?
Thanks in advance.
Light waves can be thought of as radio waves that you can see. Because both are electromagnetic waves. (I've read that since my youth, but it just so happened recently I started wondering why I never heard about radio wave photons, until I looked it up online and there were articles talking about radio wave photons.)
It would be easy to say a bulb is a radiating antenna of visible light (so is an LED, etc.). But I think your question is about light coming from a wire by electrical oscillations.
Light has such a tiny wavelength that a radiating antenna would need to be tiny.
So can a metal antenna carry vibrations of that high a frequency? It's unlikely. The innate inductance is enough to squelch such rapid oscillations. Because even in a plain wire there is inductance coming into action at those frequencies.
And I have never seen light flashes coming from a radio antenna.
If it is possible to have infra red communication which has a longer wavelength than Visible light and if it is possible to have radio wave communication which has a wavelength shorter than Visible light why is it not possible to have Visible Light Communication through Antennas? (Note that I am not talking about optic communication. It's an entirely different concept).
Thanks in advance
You are applying thought experiments, based on the information you have acquired. This is good.
As a student I learned about how both light and radio waves are electromagnetic energy. However their properties are so different, that I have trouble getting my mind around the idea they are in the same electromagnetic spectrum, only at different wavelengths.
Here are questions I ask in an effort to get to the bottom of it:
* Radio waves can pass through walls. Light waves cannot. What is so different about one compared to the other?
* We hear about light being composed of photons. We don't typically hear this about radio waves. Why?
* And if radio waves are composed of photons, then what is special about them that they can go through walls, if light photons cannot go through walls?
* Radio waves can induce electrical activity in a wire. This doesn't happen with light waves. Why is this?
* The word 'magnetic' is part of the word electromagnetic. It's easy to believe radio waves are related to magnetism. However do we think of magnetic fields as electromagnetic waves or electromagnetic anything. What differences and similarities are operating here?
* And if radio waves are related to magnetism, then why don't we think that way about light waves? Do light rays ever operate in a fashion related to magnetism?
More reading might answer some of the above questions, as far as telling what physicists observe. However I get the idea it will take continued effort to get to the root of why.
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To answer your question about infrared. Such communication is the same as optical. A remote control produces infrared beams, rapidly on and off. The same can be done with visible light.
Audio signals can also be carried on infrared by varying its intensity. The same can be done with visible light.
A infrared photodetector works about the same as a photodetector of visible light.
Visible light is used to transmit through fiber optics. Lasers produce the light beams, as I understand it.
If we looked from the side, our eyes would not see the light rays traveling through the clear class. Unless they hit an object perhaps.
If we were to look into the end of the fiber we would be blinded.
What if the light rays were infrared? Our eyes would feel heat though they would not see any light (I think).
What if the light rays were ultraviolet? We would see nothing. However our eyes would be injured. A welders must shield his eyes from the arc because it carries strong ultraviolet.
Different by which property? Antennas are bound to EM wave wavelengths. For mm waves, dipoles are still resonable antennas, although you'll rarely find single dipoles. For "μm waves" (infrared radiation) regular antennas become useless.
If you identify "optical communication" with modulations of wide band, non-coherent sources, e.g. IR LEDs, there is actually a principle difference. If you advance to mono-mode lasers, that are often used in high speed data transmission, there isn't this "different concept" any more.
To answer your question directly, when sending high speed data at a visible wavelength, you'll most likely perceive a coloured light (red, green, blue, whatsoever) but no visible modulation, because you can't see GHz signals. So it looks just like a coloured light.
P.S.: A the bottom, no principle difference between radio frequent and optical range electromagnetical waves can be determined, there's only a different form of appearance according to the large wavelength ratio.
You mean it's indeed possible to modulate visible light?
Thanks in advance.
In my view, a laser diode does, also an electro-optical modulator.
Nice post..... I've done some short range IR wireless communication last year to pass audio streams from my mobile to an audio amplifier. But it did not worked beyond 6 cm due to noise from fluorescent lamp.
And visible light comm. is obviously possible.