Questions tagged [diffraction]

Diffraction is defined as the bending or flaring of light around the corners of an obstacle or aperture into the region of geometrical shadow of the obstacle. This flaring is consistent with the spreading of wavelets in the Huygens construction. Diffraction occurs for waves of all types, not just light.

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Relationship between slit size and wavelength in diffraction

Almost in every book on physics we can find a statement like "diffraction gets stronger when the size of the slit is comparable to the wavelength". Let's say we have a wall in a bathtub with a slit in it. When water waves reach the slit, the books…
user37433
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Why do we see a rainbow of colors reflected off a CD or DVD?

So, we all know if you shine some light on CD (compact disc) or DVD, you can see all the colors from red to violet. What is bothering me is what is the reason of why do we see the colors on compact disc? I know that CD has tiny pits/bumps (order of…
solidbastard
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Why are electromagnetic waves not able to pass through a hole with a diameter smaller than the wavelength?

I am doing research on Faraday cages for school, and I want to know how it works. Faraday cages can have holes in them, and if the diameter is smaller than the wavelength of waves you want to block, the Faraday cage blocks the waves. I have found a…
E Hekkelman
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Trying to combine red, green and blue to produce white

I tried to mimic the mechanism of typical screens to produce white color out of red, green and blue. What I did is displayed the attached image on the screen, and moved far away as to let the diffraction effects take place, so that the three colors…
kalkanistovinko
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Why do two blurry shadows, when brought close to each other, appear to "bulge" and merge?

I have recently noticed that when two objects with blurry shadows cast by the same light source are brought close to each other, their shadows appear to merge in a way where one shadow appears to "bulge" and meet the other even though the two…
TheLastAirbender
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Reverse of diffraction

Can we arrange a practical in such a way that the dark and bright bands in diffraction grating be allowed to pass through the same slit to get the original light (i.e the incident light before diffraction), just like we reverse the arrows in…
Syed Hasnain Ahmed
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Does the diffracted electron radiate photons?

When electron is diffracted after the slit it might follow different direction, than before the slit. That means, that going through the slit it gains some acceleration. And accelerated charge emits photons. Thus - does the diffracted electron…
Paweł Tokarz
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What's the origin of the flattened X that appears when of a small (but powerfull enough) light is reflected in our non-powered TV screen?

The reflection of a small light (but with enough power) on our TV shows four emerging rays. The rays vary periodically in space and have a repeating pattern of the colors of the rainbow. The further the flame is from the TV the greater the distance…
Deschele Schilder
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Why does a wave actually diffract?

I know that waves diffract around a slit and this is due to the Huygens-Fresnel principle. But I never understand this in an intuitive wave that why does a wave become a spherical wave front at the slit? Huygens principle gives all the math behind…
rahulgarg12342
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Technical explanation of "Hitachi lensless camera"

Hitachi is bragging about a thin lensless camera. I can't find any technical information on how it works---just press releases etc.† Can anyone work backwards from the published descriptions to reconstruct how this works? The "concentric-circle…
Steve Byrnes
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DIY Spectrophotometer doesn't work properly in the IR range

I've built an optical spectrometer by following the instruction given on the Theremino website: Theremino_Spectrometer_Construction.pdf , but I'm having a little issue with it. Everything works perfectly fine from UV to red wavelengths, but whenever…
Matthew_R
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Why do diffractions spikes from small aperture not have fringes?

Small aperture in a photo camera leads to well-known starburst effect: (source) It's generally believed to be caused by diffraction . But since diffraction is a wavelength-dependent phenomenon, it should have rainbow-like fringes — or, for…
Ruslan
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What is the length of a photon?

Some questions that look kind of similar have been asked before, and I find the answers quite confusing. I intend to ask this question in a way that clearly shows what I'm asking. Imagine the following thought-experiment. (I don't know whether it's…
J Thomas
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How fat is Feynman’s photon?

According to my calculations, it is a lot skinnier than Airy’s photon, but still a whole lot fatter than a straight line. So, how does a photon get from point A to Point B? The ray optics approximation treats a photon as an infinitely skinny…
Jim Graber
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Is diffraction affected by interaction between photons and electrons?

Suppose we take a sheet of ordinary metal, make a narrow slit in it, and shine a light beam through the slit onto a screen. The light beam will diffract from the edges of the slit and spread out onto the screen. Now let's take an identical sheet,…
Mark Dominus
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