![]() This is due to the addition, or interference, of different points on the wavefront (or, equivalently, each wavelet) that travel by paths of different lengths to the registering surface. The characteristic bending pattern is most pronounced when a wave from a coherent source (such as a laser) encounters a slit/aperture that is comparable in size to its wavelength, as shown in the inserted image. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. ![]() Infinitely many points (three shown) along length d d project phase contributions from the wavefront, producing a continuously varying intensity θ \theta on the registering plate. ![]() Italian scientist Francesco Maria Grimaldi coined the word diffraction and was the first to record accurate observations of the phenomenon in 1660. The diffracting object or aperture effectively becomes a secondary source of the propagating wave. You represent a very large group of people who choose to answer questions on the Web on topics with which you aren't familiar.Diffraction is the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. On this site we make some mistakes, but we try to stay away from the topics where we're clueless. You can derive the entire thing from Maxwell's equations, just given the conductivity and geometry of the slit material. It's been understood in greater depth since the development of Maxwell's equations in the 1860's. The basic effect was understood when Young presented his results to the Royal Society in 1803. The phenomenon isn't "poorly understood". There's generally no frequency shift and no loss of coherence with the directly transmitted wave, unlike the picture you gave.Ĥ. The wave isn't absorbed and re-emitted later as fluorescence, but simply scattered. The wave penetrates even a good conductor to roughly one "skin depth", in this case many atoms thick, not about one atom.ģ. Diffraction (this isn't "refraction") works with fairly thick slits.Ģ. haha! Regards,īill- I wish I could say that was close, but it's pretty far off.ġ. Please nominate me for the Nobel Prize in Physics!!. I have a brief write-up on this "theory", send me an email and I'll forward it to you. no one has been able to explain this ever since Young first discribed the diffraction phenomenon. The process does not work well when slit material thickness exceeds the ability of the impinging photon to penetrate the material completely. So the poorly-understood "bending of light" around slit edges is dominantly a refraction process. As the electron energies fall-back to their 'normal' state, the excess energy is emanated as secondary photonic energy - probably of a frequency close (or harmonic?) to that of the impinging photon. ![]() Photonic energy is transferred to outer electrons of the slit material atoms, raising their (atom electron) energy levels. Refraction is induced where photons hit very thin parts of the slit (ideally monoatomic +/-thicknesses). The interaction actually 'refracts' those photons, electrons, etc. ![]() Nacho: Certainly light interacts with the edges of slits. My response to a question posted on Physics Forum. ![]()
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