What causes light to bend when passing the edges of objects?

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Discussion Overview

The discussion revolves around the phenomenon of light bending or spreading when it passes the edges of objects, focusing on the concept of diffraction. Participants explore various explanations, analogies, and the underlying principles of wave behavior in light, comparing it to other types of waves such as water and sound waves.

Discussion Character

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

Main Points Raised

  • Some participants express confusion about why light bends when passing edges, questioning the mechanisms behind this behavior.
  • Others argue that light does not bend but spreads out due to diffraction, with some suggesting that each part of a wavefront acts as a wave generator.
  • Analogies are drawn to water waves and sound waves, with participants discussing how these waves diffract and the differences in their properties compared to light waves.
  • One participant suggests that diffraction can be explained using the uncertainty principle, while another counters that diffraction is a classical property that does not require quantum explanations.
  • There is a discussion about the differences in wave propagation mechanisms between light and other types of waves, with some emphasizing that light waves do not have adhesion properties like water waves.
  • Some participants highlight that diffraction is caused by the spatial truncation of a wavefront, while others seek a deeper understanding of why light bends in a specific direction when encountering edges.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the explanations for light bending or the comparison of light with other wave types. Multiple competing views remain, particularly regarding the role of wave properties and the applicability of the uncertainty principle.

Contextual Notes

Some participants acknowledge gaps in their understanding of the laws governing these phenomena, and there are unresolved questions about the fundamental reasons behind the bending of light at edges.

  • #31
Born2bwire said:
Then what is your objections to the explanations given previously? To whit, we have mentioned Huygen's Principle and Equivalence Source Principle to explain diffraction. For refraction we can explain it by the fact that boundary conditions require that the phase of the wave be continuous across the interface in addition to the fact that the wavelength changes as well.

Please give me the textual material of latest mathematical proofs that you are telling about or just send me their links then I will explain you about my objections. Please Believe
 
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  • #32
IrshadAlam said:
Please give me the textual material of latest mathematical proofs that you are telling about or just send me their links then I will explain you about my objections. Please Believe

Just about any electromagnetics textbook should be sufficient. For refraction you can look at say Balanis "Advanced Engineering Electromagnetics," Chew's "Fields and Waves in Inhomogeneous Media" or probably Kong's textbook as well. Balanis should be sufficient for diffraction as he has an entire chapter on the subject and of course I already made mention of Sommerfeld's treatment of the problem which is often used as a starting point in many diffractiont theories.
 
  • #33
IrshadAlam said:
Please give me the textual material of latest mathematical proofs that you are telling about or just send me their links then I will explain you about my objections. Please Believe

These 'latest mathematical proofs' are pretty ancient and you can find them, as has been said, in so many established texts. That doesn't mean they're flawed, though. Explain your objection to those proofs first and show how introducing photons actually improves on them.
You will, of course, need to characterise the photon very fully, with regard to its extent, shape etc. and, possibly, how it will interact with other photons whilst it's going from A to B. You may find that a bit difficult.
 
  • #34
sophiecentaur said:
These 'latest mathematical proofs' are pretty ancient and you can find them, as has been said, in so many established texts. That doesn't mean they're flawed, though. Explain your objection to those proofs first and show how introducing photons actually improves on them.
You will, of course, need to characterise the photon very fully, with regard to its extent, shape etc. and, possibly, how it will interact with other photons whilst it's going from A to B. You may find that a bit difficult.

Anyhow I can do that.
 
  • #35
Go on then. There be dragons.

I'd have a problem doing it as I don't 'believe in photons' in the way that so many people do. I, of course, believe in the photoelectric effect and quantum mechanics etc. - but they are both concerned with interactions.
 
  • #36
Please forgive my density but consider a slit:
|

|

Now magnify the slit until you see the edges
u

n
The edges of the slit actually have thickness. (I am not talking about the gap, I am referring to the thickness of the material in which the slit is cut)

Does diffraction change as the material gets thinner and thinner? In other words, is the diffraction greater if the material is thinner than the wavelength ?

Experimentally, I think it would be easier to increase the wavelength and keep the material the same, but you get the idea.
 
  • #37
Of course the edges must have an effect. All real objects have depth and they produce their peculiar diffraction patterns. If you take it to an extreme, you could have two 'pipes' with light emerging and they would also have a distinct pattern - but whether you could detect the difference would be another matter. :smile:

Remember that a hologram is merely the diffraction pattern of a three dimensional object.
 

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