Timeline for Is refraction sharp or smooth?
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
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| Apr 29, 2014 at 22:12 | vote | accept | SuperCiocia | ||
| Apr 27, 2014 at 0:17 | comment | added | dmckee --- ex-moderator kitten | The key point here is that if the physical situation is examined at very high resolution (comparable to atomic length scales) ray optics ceases to be a good approximation and you have to work directly with the field equations in the presence of matter. | |
| Apr 26, 2014 at 19:05 | comment | added | garyp | That is correct. But it doesn't answer the question "sharp or smooth". What's up for discussion is the details near the interface. | |
| Apr 26, 2014 at 18:07 | comment | added | SuperCiocia | I was thinking of the wavefront, so a line perpendicular to the rays in the diagrams. I was told that, when reaching the interface, part of the wavefront is in the higher refractive region while the rest of it is still in the lower one, so that the former moves slower while the latter keeps its initial speed. This causes the ray to turn. Is this just an intuitive / heuristic explanation or is there something true? | |
| Apr 26, 2014 at 17:50 | history | edited | garyp | CC BY-SA 3.0 |
Gave an explanation for my approach, and added "Huygens scatterers" point of view.
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| Apr 26, 2014 at 15:37 | comment | added | garyp | Countless other rays: I'm thinking of scattering off of atom-scale fluctuations (atoms), in the way that the macro Maxwell equations follow from the micro eqns. Quantum physics: the question can be answered purely classically. QM is not needed to derive Snell's law, nor for this discussion. Photons: ditto. Imperfections smaller than wavelength: will cause diffraction. Average values: yes, that would be an alternate model midway between my microscopic picture and the abrupt ideal picture. Rays curve in that model, but it is another idealization, ignoring micro physics. Out of room! | |
| Apr 26, 2014 at 14:38 | comment | added | Blackbody Blacklight | Can you clarify "countless other rays"? The photon is best modeled as a wavefunction, not a ray, and interference is a field effect. Quantum physics is the right tool for interface region analysis. I think it comes down to the interface imperfections being much smaller than the wavelength, hence no diffraction. On that smaller scale, what matter are average values of permittivity and permeability, and that does suggest a smooth transition. | |
| Apr 26, 2014 at 14:01 | history | answered | garyp | CC BY-SA 3.0 |