Is visible light just composed of photons?

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Gail Ethier

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Is visible light just composed of photons?
« on: 06/09/2008 15:43:57 »
Gail Ethier asked the Naked Scientists:

Light can act as a wave or a particle, but light is just one part of the
electromagnetic spectrum.  Is a photon just in the visible light area of the
spectrum?  Is there such a thing as a 'microwave photon' or 'ultraviolet photon'?  Do other wavelengths of electromagnetic energy act as a particle?

What do you think?




Edited title to create a better question
« Last Edit: 07/09/2008 18:11:12 by ukmicky »

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Offline lightarrow

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Re: Is visible light just composed of photons?
« Reply #1 on: 06/09/2008 15:52:10 »
Gail Ethier asked the Naked Scientists:

Light can act as a wave or a particle, but light is just one part of the
electromagnetic spectrum.  Is a photon just in the visible light area of the
spectrum?  Is there such a thing as a 'microwave photon' or 'ultraviolet photon'?  Do other wavelengths of electromagnetic energy act as a particle?

What do you think?
For infrared or higher frequencies, that is: visible light, UV, X-rays, gamma rays, ecc., it's proved. For microwaves I'm not sure, but for lower frequencies, it's still not proved experimentally that they are made of photons. There is however no theorethical reasons to think they are not. (But without the experimental prove...)

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Offline Bored chemist

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Re: Is visible light just composed of photons?
« Reply #2 on: 06/09/2008 18:35:09 »
Microwave spectroscopy is good evidence that microwave radiation is also quantized.
Similarly, NMR spectra are recorded with radio frequency radiation.
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Offline lightarrow

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Re: Is visible light just composed of photons?
« Reply #3 on: 06/09/2008 20:31:02 »
Microwave spectroscopy is good evidence that microwave radiation is also quantized.
Similarly, NMR spectra are recorded with radio frequency radiation.
Ok, but this is not exactly the same as saying that the radiation is made of photons. You should prove the existence of effects like the "antibunching effect", otherwise you can describe the existence of spectra as a quantized interaction between a classical EM field and a quantum system (at least this is what I heard).