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.
Questions tagged [diffraction]
1181 questions
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How does light bend around my finger tip?
When I close one eye and put the tip of my finger near my open eye, it seems as if the light from the background image bends around my finger slightly, warping the image near the edges of my blurry fingertip.
What causes this? Is it the heat from my…
Daniel A.A. Pelsmaeker
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Why do shadows from the sun join each other when near enough?
I was laying on my bed, reading a book when the sun shone through the windows on my left. I happened to look at the wall on my right and noticed this very strange effect. The shadow of my elbow, when near the pages of the book, joined up with the…
turnip
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Why does wavelength affect diffraction?
I have seen many questions of this type but I could nowhere find the answer to "why". I know this is a phenomenon which has been seen and discovered and we know it happens and how it happens. But my question is why would wavelength affect the amount…
rahulgarg12342
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Why exactly does diffraction occur?
Why do waves that were traveling in a straight direction change direction when passing through an opening?
I thought that the waves (red arrow) when colliding with the wall bounce in the opposite direction (green arrow).
And the waves that pass…
jony alton
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What is the difference between diffraction and interference of light?
I know these two phenomena but I want to know a little deep explanation. What type of fringes are obtained in these phenomena?
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How is momentum conserved in diffraction?
Sigh. Approaching retirement age and still deeply confused about something I first encountered in highschool 40 years ago.
Consider the usual double slit experiment. Make the light source be a laser with a beam 1 mm wide. And put it 5 meters away…
Dan
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Why does light reflected from an LED TV screen make a sharp X pattern?
If you shine a laser pointer or generally any coherent light at the screen of a fancy, new TV, you get a very sharp X pattern.
I think this is a property of LED screens specifically. This phenomenon has been noted many times (1, 2, 3, 4), but…
knzhou
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Do black holes have Arago spots?
I've been reading about Arago spots and the Aragoscope. Some fascinating concepts! Basically, due to wave diffraction, there is a bright spot in the centre of the shadow behind any circular object.
It strikes me that there are some similarities…
craq
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What did I just photograph? (rainbow way out of place)
I just captured the following two pictures. Straight above me, almost directly above, was a rainbow, about 120 degrees of it were visible.
The thing is, the sun was completely out, low on the horizon and not centred. What explains this? My…
Jeffrey
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Squinting at street lights
Simple question, I've always wanted to know the answer to this.
Why do you see a pair of lines radiating out from street lights when you squint at them? I can't think of a better way to describe what I mean, but I hope someone knows what I'm talking…
user5335
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Why do I see three 'beams' when I look to a distant light source at dark?
In the night, when I look at a distant light source (for example a street lamp a few hundred meters away) I do not simply see a spot but rather a spot which is surrounded by 'light beams'.
So instead of seeing the image on the left-hand side of the…
Tho Re
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Amateur moon laser ranging
Questions first, then my rough estimations:
Is it possible to perform moon laser ranging with amateur motorized 114 mm telescope? My calculations suggest that for 1 mJ laser it should receive ~2 photons per source 1 mJ laser pulse.
Given that we…
BarsMonster
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What is causing the diffraction pattern on my ceiling?
When I wake up in the morning and look at my curtains, I see a pattern on the ceiling made by the light going through the gap between my curtains. I have added a picture of it below. I remember from high school that when a laser was being shot…
user3635700
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Optimal telescope size?
Consider a diffraction-limited telescope with unobstructed aperture $D$. Such a scope is capable of yielding an angular resolution $\alpha$ that scales as $\lambda/D$, with $\lambda$ denoting the wavelength of the light. However, in reality such a…
Johannes
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Difference Between Fraunhofer and Fresnel Diffraction
What is the difference between Fraunhofer diffraction and Fresnel diffraction? I mean diffraction is just bending of light waves or waves in general around a point. So how can there be two types of diffractions?
If Diffraction means something else…
Isomorphic
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