Does the material of the slits wall influence the diffraction of light? I mean, imagine if the material where the slits were made had electromagnetic properties, wouldn't that influence in some way the diffraction and interference?

Basically, does the electromagnetic properties of the material where light diffracts change its path? I'm sorry if I am not 100% correct, I'm starting to study physics and this experiment absolutely fascinantes me. A 200 year old problem where the current solution is something out of fiction!

  • $\begingroup$ You have to work pretty hard to measure a dependence on the properties of the blocking material without introducing a degree of transparency at the edges, but it is certainly there in principle. That said, the double slit experiment isn't a problem: in the classical version it is completely understood and using it on quantum system simply points out that quantum systems are different from classical one. $\endgroup$ – dmckee Feb 4 '17 at 19:10
  • $\begingroup$ A 200 year old problem where the current solution is something out of fiction Can I suggest, as this aspect of physics is in the top ten list of questions here , that you search through this site, or using G with the words physics stackexchange included, and you can see how wave/particle is dealt with in modern terms . $\endgroup$ – user140606 Feb 4 '17 at 20:02
  • $\begingroup$ Welcome fsx. Can the intensity distribution behind edges and slits be explaint by the interaction with the surface electrons of the edges?. May be that idea is similar to yours? $\endgroup$ – HolgerFiedler Feb 4 '17 at 21:02
  • $\begingroup$ @HolgerFiedler it is indeed very similar. Happy to see I'm not alone in finding this fascinating. $\endgroup$ – fsx Feb 4 '17 at 21:30
  • $\begingroup$ Your question actually concerns how exactly photons(electrons) interact with the obstacle. If they interact with some average electric field, as it most certainly is, then material should not matter so much. Energy of the field probably also doesn't matter if it is above certain value. I am surprised that someone with more experience have not answered this. $\endgroup$ – Baj Mile Feb 28 '17 at 12:46

I am surprised that there isn't more comprehensive answers to this question from more experienced people. I will try to fill the gap because the topic how material properties influence diffraction pattern is very interesting and is somehow neglected in the physics books. A more complete answer however should be given from someone with rich experimental experience.

The question seems simple but needs deep understanding in several fields.

First, you have to get introduced with the diffraction grating effect - the separation of the colors of the light through diffraction. It acts as a "super prism", separating the different colors of light much more than the dispersion effect in a prism.

Second, it have been known that the magnetic properties of the materials changes the angles by which light is diffracted. This is called Magneto-optic Kerr effect (MOKE) . MOKE is a result from the Faraday effect. It depends if the magnetization vector is parallel or perpendicular to the plane of incidence, light may be diffracted differently in each case because the magnetic field changes the polarization plane.

Third, the temperature of the grating material (the thermal energy of its particles) also matters. It changes the wavelength of the radiated light and doing so will change the colors in the diffraction pattern. For introduction about temperature influence of the radiation you can read about the Black-Body radiation.

So both magnetic and thermal properties influences diffraction. Actually, one of the pioneers in the diffraction optics - Wilhelm Wien, have studied exactly such effects in his PhD thesis called "On the diffraction of light upon photographically miniaturized lattices" but I couldn't find the original text in English.


Your question is a very good one and I want to support your thoughts.

First, there has to be an interaction between the light and the material of the edges. Light is electromagnetic radiation and by this it has an electric and a magnetic field component. These fields are oscillating. So during the transition of the lights units (photons) there is a periodical influence of the photons fields to the surface electrons of the edges material.

Second, the edges we use for diffraction experiments are always thin (Thin in the meaning that the edges are sharp like from a knife or blade). Why this could be important? It is known that for a charged body the discharge of this body happens preferred on spices or other protruding contours. Thin edges further the formation of a common field between the edge and the photons.

Third, diffraction patterns occur not only behind double slits but behind single slits as well as behind every sharp edge. And this experiments one can run with shot one by one photons; after a while the same intensity distribution occurs in the observation screen. All explanations about interference of light from the left and the right edge are obsolet for single shots and more than this behind single edges.

  • $\begingroup$ Downvotes without arguments? Why are the representatives of the pure doctrine are not willing to discuss and disprove the chain of arguments? Or is my expression too bad in English? $\endgroup$ – HolgerFiedler Feb 4 '17 at 21:43
  • $\begingroup$ "the edges we use for diffraction experiments are always thin" Speak for yourself. Thinness has to be compared to the wavelength being diffracted. The home and classroom version of the experiment rarely get the edges down to that level because the main effect is very insensitive to little details like that. If you want to do a high precision measurement you have to attempt to have thin edges for the slits which is one of the difficulties of doing a precision diffraction experiment with visible light. $\endgroup$ – dmckee Feb 5 '17 at 2:38
  • $\begingroup$ @dmckee Are you speaking for or against the thinness of the slits? Slit experiments are carried out with blades, knifes, coated glass, foils and so on. I'm curious if it was carried out with holes or slits in say metal sheets of mm or cm thickness. Please share your experience. $\endgroup$ – HolgerFiedler Feb 5 '17 at 6:06
  • $\begingroup$ Holger, visible light has a wavelength of a few hundred nanometers. A layer only 10 microns through should be regarded as 'thick' not as 'thin': human scales don't matter to this question. Yes, a very good knife-blade aperture is thin, but those are rare in a demo context. Instead we literally use human hairs, fine wires, slits in aluminum foil all of which are thick. Other demo materials like scraped surface layers on glass may cover the range from one wavelength to many. Do you know how think the one in your hand is? $\endgroup$ – dmckee Feb 5 '17 at 17:37
  • $\begingroup$ @dmckee there is a misunderstanding or better, perhaps there is a wrong expression of mine. I'm not relating the thinness of the slits material to any wavelength. To be more precise about the thinness, the material can be thick, but in the area of the slit the slit has to have sharp edges. $\endgroup$ – HolgerFiedler Feb 5 '17 at 17:48

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