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AlanPartr
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I was wondering if anyone knew why light (or any other particles) diffracts when it goes through an aperture?
Why Does Light Diffract? Exploring the Phenomenon of Diffraction in Particles
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In summary, Alan was wondering if anyone knew why light (or any other particles) diffracts when it goes through an aperture. Feynman's book QED explains it in terms of waves and particles.
- #2
Ambitwistor
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If you want an answer to this question in terms of particles, rather than waves, you can do no better than to read Feynman's book QED: The Strange Theory of Light and Matter.
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Integral
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This is due to the wave nature of light. It is was well documented in the 19th century. You may wish to research the work of Fresnel and Fraunhofer for the classical presentation.
For the particle aspect of it read QED by Richard Feynman.
For the particle aspect of it read QED by Richard Feynman.
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Chi Meson
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THe quantum explanation is currently the best explanation, and for that you would need to read Feynman's "QED" (it's a thin book that takes a long time to read). BUt before reading this book, you need a full-year of introduction to physics, including basic vectors (vector arrows are used when analyzing photons, but they are called "amplitudes" which actually means "probability.")
The best thing about Feynman's QED is that the same explanation also explains refraction, reflection and interference. This is the kind of simplification that Physics is all about.
In an undeniably insufficient explanation:
Photons will take a certain path that will require the least amount of time to reach a point at which there is a greater-than-zero probability of existing there. Due to the nature of all the possible paths for the photon, there will be points of higher and lower probability (that the photon will be there) Bright diffraction "fringes" indicate zones of high probability and dark "fringes" indicate regions of near zero probability.
IF you want the old explanation of "why diffraction of light" then you must follow the wave model. Do a google search for "Huygens' Principle." It's not easy either, and it's also incorrect for light (according to our current, most accepted explanation).
The best thing about Feynman's QED is that the same explanation also explains refraction, reflection and interference. This is the kind of simplification that Physics is all about.
In an undeniably insufficient explanation:
Photons will take a certain path that will require the least amount of time to reach a point at which there is a greater-than-zero probability of existing there. Due to the nature of all the possible paths for the photon, there will be points of higher and lower probability (that the photon will be there) Bright diffraction "fringes" indicate zones of high probability and dark "fringes" indicate regions of near zero probability.
IF you want the old explanation of "why diffraction of light" then you must follow the wave model. Do a google search for "Huygens' Principle." It's not easy either, and it's also incorrect for light (according to our current, most accepted explanation).
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Chi Meson
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Dang it!
Why can't I ever get the first word in?
Why can't I ever get the first word in?
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Integral
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It is reassuring that we all posted the same reference! 
- #7
Ambitwistor
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I don't want to scare Alan off ... Feynman's book was based off of lectures intended for laymen, and I think you can absorb a great deal from it without prior exposure to physics or vectors.
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AlanPartr
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cheers
cheers
looks like I've got some reading to do
cheers
looks like I've got some reading to do
- #9
Adrian Baker
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You only need to read the first two chapters (of four).
My 16/17 year old Physics students are all told to read it - they cope (just about), so don't be put off Alan. It is a very good book.
1. Why does light diffract?
Light diffracts because it behaves as a wave. When light encounters an obstacle or passes through a narrow opening, it bends around the edges and spreads out, which is known as diffraction.
2. What causes light to diffract?
The diffraction of light is caused by the wave-like properties of light. When light passes through an opening or encounters an obstacle, it spreads out and bends around the edges due to interference between the different parts of the light wave.
3. How does the wavelength of light affect diffraction?
The wavelength of light has a direct impact on the amount of diffraction that occurs. The smaller the wavelength of light, the less it diffracts, while longer wavelengths diffract more. This is why we see more diffraction with red light compared to blue light, as red light has a longer wavelength.
4. Can diffraction be observed with all types of light?
Yes, diffraction can be observed with all types of light, including visible light, UV light, and infrared light. However, the amount of diffraction may vary depending on the wavelength of light.
5. What are some real-world applications of diffraction?
Diffraction is used in a variety of real-world applications, such as in optical lenses, to create holograms, and in the production of CDs and DVDs. It is also used in scientific experiments, such as X-ray crystallography, to study the structure of molecules.
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