Is it possible to create light?

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Discussion Overview

The discussion revolves around the possibility of creating light using electric and magnetic fields, exploring both theoretical and practical aspects of light generation, including visible light and electromagnetic radiation. Participants also touch on related concepts such as laser cooling, the behavior of light in different media, and the implications of relativity.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that light can be created using electric and magnetic fields, referencing antennas and radio transmitters as examples.
  • Others argue that while electromagnetic radiation can be generated, directly producing visible light through oscillating electric fields remains challenging.
  • A participant mentions the recent development of electrically operated light antennas as a potential advancement in generating light.
  • There is speculation about the efficiency of converting energy into light, with one participant expressing interest in a specific article on the topic.
  • Some participants discuss the implications of slowing down light, questioning whether this affects its properties or the concept of relativity.
  • One participant suggests that passing light through electric or magnetic fields might change its wavelength, but expresses difficulty finding sources to support this idea.
  • Another participant clarifies that the speed of light remains constant in a vacuum and that slowing light in a medium does not change its fundamental properties.
  • There is a discussion about the frame of reference of photons, with some participants asserting that a photon does not have a meaningful frame of reference in relativity.
  • One participant mentions that atoms at very high temperatures may not behave as traditional atoms, potentially forming plasma.
  • Another participant highlights that light emission from excited atoms is a fundamental source of light, linking it to quantum electrodynamics.

Areas of Agreement / Disagreement

Participants express a mix of agreement and disagreement on various points, particularly regarding the generation of visible light and the implications of relativity. No consensus is reached on several speculative ideas, and multiple competing views remain throughout the discussion.

Contextual Notes

Some claims about the efficiency of light generation and the behavior of light in different media are not fully substantiated, and there are unresolved questions about the implications of slowing light and the nature of frames of reference in relativity.

fredreload
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Is it possible to create light with electric field and magnetic field since light is a type of electromagnetic radiation?

P.S. With laser cooling you can slow down light to 38MPH.
 
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fredreload said:
Is it possible to create light with electric field and magnetic field since light is a type of electromagnetic radiation?
Yes it is. In fact, you might have posted the message above by creating light. All you need is an antenna and a radio transmitter (both commonly used in your cell phone's Wi-fi communication): https://en.wikipedia.org/wiki/Antenna_(radio)

If you mean visible light, we don't yet (as far as I'm aware) have a good way of directly generating oscillating electric fields at that frequency.
 
TeethWhitener said:
If you mean visible light, we don't yet (as far as I'm aware) have a good way of directly generating oscillating electric fields at that frequency.

https://www.uni-wuerzburg.de/en/sonstiges/meldungen/detail/artikel/die-erste-elektrisch-betriebene-lichtantenne-der-welt/
 
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Well whaddaya know? Neat.
 
DrStupid said:
https://www.uni-wuerzburg.de/en/sonstiges/meldungen/detail/artikel/die-erste-elektrisch-betriebene-lichtantenne-der-welt/
Very cool. Now if we can just turn that around into visible light rectennas, we might have the next step in photovoltaic efficiency improvement... :smile:
 
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berkeman said:
I wonder how efficient the conversion was.

0,00005 %
 
DrStupid said:
0,00005 %
Ouch! Okay, you just saved me $36... :smile:
 
  • #10
I was thinking by passing light through electric field or magnetic field the wavelength might change, since they are made from these two components, but I can't seem to find any source on it on Google. Now that we've slowed down light to 38mph, is there a change in relativity sense of light? I've heard that someone mentioned this concept can be used for data storage but I haven't really looked into it.
 
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  • #11
fredreload said:
Now that we've slowed down light to 38mph, is there a change in relativity sense of light?
Nothing has changed about the properties of light. It still travels at c in a vacuum and at lower speeds in other materials.
 
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  • #12
How about this formula? Just speculating, well I thought it is interesting to put 38^2 in the formula.
 
  • #13
You should not think of "c" in most relativity-related formulas fundamentally as the "speed of light (in a vacuum)", but rather as the "universal speed limit" or "universal invariant speed". Light happens to travel at that speed because it's associated with massless particles. Other massless particles also travel at that speed. If photons had mass, light (in a vacuum) wouldn't travel at speed c.
 
  • #14
fredreload said:
How about this formula? Just speculating, well I thought it is interesting to put 38^2 in the formula.

Interesting but meaningless, as the ##c## in that equation is the speed of light in vacuum, not a medium.

However, it's mostly for historical reasons that we say "##c## is the speed of light". ##c## is a constant of nature in its own right, and if it ever turned out that light in a vacuum did not move at ##c## (which is not going to happen) we wouldn't say that we were wrong about the value of ##c##, we'd say that we wrong about the behavior of light.
 
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  • #15
How about this one? If I am a photon (it doesn't need to be in a vacuum right?) I would see that any distance I want to travel to is close to zero (if I remember what was taught in high school Physics). Then suddenly I am slowed down to 38mph and an entire universe appeared. Now this doesn't mean you need to be in an Einstein-Bose condensate to feel this? Then again why do I need to create more distance for myself by putting myself inside an Einstein-Bose condensate.
 
  • #16
fredreload said:
How about this one? If I am a photon (it doesn't need to be in a vacuum right?) I would see that any distance I want to travel to is close to zero (if I remember what was taught in high school Physics). Then suddenly I am slowed down to 38mph and an entire universe appeared. Now this doesn't mean you need to be in an Einstein-Bose condensate to feel this?
There is no such thing as the frame of reference of a photon so your question is not meaningful.
 
  • #17
Well, there is a frame of reference for an object close to the speed of light right? Is having a mass a requirement?

Credit:
 
  • #18
There is a series of severe misunderstanding here that should have been corrected.

First of all, one needs to clearly understand what is meant by "the speed of light" that the OP is referring to, and this is especially the case when we are talking about the speed of light in a medium. This is the group velocity of light! That is what being slowed down in a medium.

Secondly, light has been slowed down, but has been slowed down to ZERO m/s. This means that it has been stopped, held for some time, and then "replayed" back (this is different than light being absorbed completely by an opaque object).

Thirdly, an antenna generating EM radiation is the same as having a bunch of charge, such as a bunch of electrons, being jiggle up and down (or left and right, etc.). This is similar to what is being done in the numerous synchrotron light sources all over the world, and in the many FEL facilities around the world. Most of the light being generated (including, in principle, visible, UV, IR, etc.) are bunches of electrons passing through an insertion device such as a wiggler or undulator that causes the passing bunches to jiggle back and forth, just like what you do in an antenna due to the moving current.

Zz.
 
  • #19
fredreload said:
Well, there is a frame of reference for an object close to the speed of light right?
Yes there is. What does that have to do with the current discussion?

Is having a mass a requirement?
A requirement for what? Having a frame of reference? Then, yes, in that massless objects travel at c and have no frame of reference.
 
  • #20
Well, here's a discussion about Photon's frame of reference. So I suppose I'll just leave it at laser cooling, sorry about that. How about anything at high temperature? Anyone got a video on that?
 
  • #21
fredreload said:
Well, here's a discussion about Photon's frame of reference.

That discussion simply re-enforced the idea that such a reference frame doesn't exist in Relativity (look at the postulates of Special Relativity). You need to understand that first and foremost before attempting to use anything from Relativity. Otherwise, you'll be using it in places where it wasn't meant to be used.

Zz.
 
  • #22
Well yes, that's why I left my idea at laser cooling and laser cooling is done before. And now I want some information about atom at super high temperature.
 
  • #23
fredreload said:
Well yes, that's why I left my idea at laser cooling and laser cooling is done before. And now I want some information about atom at super high temperature.

That's super vague. Atoms at "super high temperatures" are no longer atoms. They could be a plasma!

Zz.
 
  • #24
Cool, I'll look into it!
 
  • #25
fredreload said:
Well, here's a discussion about Photon's frame of reference.
No, this quickly became (after the misleading title) a thread about the fact that a photon does not HAVE a frame of reference.
 
  • #26
Hmm, it seems light can be condensed in the same way.
 
  • #27
The most obvious source for light is an atom in an excited state and the emission of a photon as the excited state. The emission of energy as a photon by the excited electron as it changes state is the result of the interaction of the excited atom with the electromagnetic vacuum field. See Weisskopf-Wigner QED theory of spontaneous emission or Quantum Optics, Scully and Zubiary,pp23- (https://books.google.com.au/books?i...en#v=onepage&q=atom transition photon&f=false) should give you a link to the eBook.
 
  • #28
DaveC49 said:
The most obvious source for light is an atom in an excited state and the emission of a photon as the excited state. The emission of energy as a photon by the excited electron as it changes state is the result of the interaction of the excited atom with the electromagnetic vacuum field. See Weisskopf-Wigner QED theory of spontaneous emission or Quantum Optics, Scully and Zubiary,pp23- (https://books.google.com.au/books?id=20ISsQCKKmQC&pg=PA430&dq=atom+transition+photon&hl=en#v=onepage&q=atom transition photon&f=false) should give you a link to the eBook.

I'm not sure by what you mean as "the most obvious source for light". For most people, the most obvious source is the old incandescent light bulb. This is definitely not a source that is due to atomic transition (look at the spectrum from such a source). One may make an argument that the fluorescent light bulbs may be such a source, but now with LEDs starting to be more prevalent, we are again moving away from sources involving atomic transitions.

Zz.
 
  • #29
In the case of an incandescent filament, the emission is black-body radiation which in Einsteins explanation of blackbody emission is as the result of excitation and relaxation of a set of discrete energy states in the surface of the metal. These are transitions of electrons associated with the conduction band of the metal and the electrons in the conduction band have a distribution of energies given by the Bose-Einstein distribution. It is still an atomic transition not from a single isolated atom but from an ensemble of atoms in such close proximity that their outer electron shells overlap to form a band of energy states.
 
  • #30
DaveC49 said:
Ithe electrons in the conduction band have a distribution of energies given by the Bose-Einstein distribution.
You mean Fermi-Dirac, right?
 

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