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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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What is the theory behind imaging a precision pinhole?

In my efforts to characterise a 0.67 NA microscope objective, I have placed a 20 micron precision pinhole at the focal plane of the objective, and back illuminated the pinhole with a 767nm laser. The ...
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Why does light keep it's direction when passing through glass?

It is assumed that light does not propagate through a different medium as such but by interacting with electrons of atoms it reaches. So photons crash into electrons of the medium's atoms, elevate ...
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How does a recordable CD that uses organic dyes to store data produce iridescent rainbow colors?

I thought that only pressed pre-printed CD-ROM can produce rainbow colors due to the parallel spiral tracks of lands and pits it uses to store data in the reflective metal layer, tracks that diffract ...
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How to get the highest order minimum in a diffraction pattern

Like the title says, I am trying to understand Diffraction patterns. I know that dsin(θ)=mλ, can be used to find the distance from the central maximum fringe, given the wavelength λ, and the angle θ. ...
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Which focal length is needed to determine minimum focused spot size in 2 lens system?

If you calculate the minimum spot size of a beam, it depends on the focal length to to power 2. But if you have a lens system with 2 lenses, does the focal length in this case represents the effective ...
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Wave scattering by crystals

The structure factor is defined as (assuming orthogonal axes): $$S_{(hkl)} = \sum_{j \in \mathcal{U}} f_j \exp\{2\pi i (hx_j+ky_j+lz_j)\},$$ where $\mathcal{U}$ is a unit cell of the lattice and the ...
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What is the purpose of the slit in a spectroscope?

I built a spectroscope using a CD as diffraction grating. I understood how the grating works, but I didn't get why the slit is essential. Shouldn't it work even without the slit?
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What is the principal cause of diffraction?

I have found another question similar to mine here. But I want to know why does diffraction of light happen in the first place. I have found other resources on google which explain the topic partially ...
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Fraunhofer diffraction problem in Python: How to interpret discrete Fourier transform (DFT) spectrum?

I have a periodic phase grating consisting of lenslets along the x-direction, invariant in y. I want to use python to calculate the far-field (Fraunhofer) diffraction pattern that one gets when ...
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Electron diffraction on crystal lattice

To observe electron diffraction, we standardly let its wavefunction pass trough a crystal lattice. However, why does not the electron's interaction with crystalline atoms cause wavefunction collapse?
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How is the diffraction (or interference) pattern in this photo explained?

I noticed the above photo on a website (https://www.aapt.org/Programs/contests/pc09full.cfm?Meeting=SM09&Category=Natural&Placing=44). How the pattern can be explained bothers me for some time....
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Diffraction of Sound Waves

We know that Sound waves are Longitudinal waves. It mean that there is pressure difference created when medium particle move. But while diffraction of sound waves 'How will the medium particles move'. ...
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Distorsion in Photoluminescence

I am studying photoluminescence, but I do not understand why during measurement it turns out that the signal is distorted due to appearance of a long-wavelength replica of the fundamental laser ...
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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. ...
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Why is intensity decreasing for higher orders of Bragg (x-ray)diffraction?

Bragg diffraction for x-rays by a crystal structure is governed by $$ n\lambda=2dsin\theta ,$$ where $n$ is an integer and the diffraction order, $\lambda$ is the x-ray wavelength, $d$ the lattice ...
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Why is a circular aperture defined by the circle function rather than a heaviside step function?

In the chapter 4 of the text "Introduction To Fourier Optics" by Goodman, the diffraction pattern of light passing through a circular aperture was studied. The diffraction pattern on the image plane $(...
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Rayleigh Criteriaon of resolution and Angular Separation

I get the Rayleigh criterion for resolution and how that is derived in terms of angle between diffraction maxima’s of the two sources. I read in a book (screen shot attached) that angular separation ...
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Diffraction limit (Rayleigh criterion) and circular image on the screen

In the angular resolution, we explain the diffraction limit (Rayleigh criterion) by showing a circular image on screen. I wonder is there an inbuilt assumption that light source is a point source.? I ...
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Derivation of Babinet's principle

I cannot understand the derivation of Babinet's principle. According to Jackson's classical electrodynamics of page 489, From the linearity of Maxwell equations and the relation between the ...
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Average square Euler's formula for trigonometric identities

We know that the average value for a squared cossine on a full period is: $$\frac{1}{T}\int_0^T\cos^2(\omega t)dt=\frac{1}{2}$$ And the same value holds for a sine. But if we use Euler's formula, then:...
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The diffraction angle of toroidal grating

I have a 300 g/mm toroidal grating (r=100 mm, R=920 mm, h=19 nm, c/d=0.51). I want to know the diffraction angle of 800 nm and 80 nm light when the AOE (angle of incidence) of them is 85 degrees, i.e. ...
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Did diffraction bend this light more than 90 degrees?

Earlier I asked whether diffraction could bend light more than 90 degrees. earlier question Lambda gave me an answer. He stuck a razor blade into a piece of wood, and he shone a green laser at it, ...
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In diffraction When wavelength is less than slit width then does the scattered light gets absorbed & emitted from the wall or just rebound?

I know that when the slit width is less than that of wavelength then the slit will act as a point source and scatter the light in all directions. But my question is that during the scattering of ...
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Does diffraction pattern depends upon thickness of slit?

I know that diffraction pattern depends upon the width of slit but does the thickness of slit also matters? If so then what happens to the diffraction pattern at variable slit thickness?
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Relationship between aperture function and Fraunhofer diffraction patern

I have read that the Fraunhofer diffraction pattern of a source is the Fourier transform of the aperture, however I have not been able to follow the proofs. All of them seem to demonstrate that the ...
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Can diffraction bend light more than ninety degrees?

Is it possible for light to be diffracted more than ninety degrees? When light diffracts through a narrow slit or pinhole, it travels in all forward directions. The width of the slit determines how ...
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Does diffraction happen from small slit width than its wavelength? [duplicate]

I always learnt in school that diffraction and interference happens if the slit width is of the order of wavelength. But what if the slit width is less than that of wavelength. Does diffraction ...
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Diffraction of electron from single slit using time dependent perturbation theory

While reading about time dependent perturbation theory, I began wondering if it was possible to obtain the diffraction pattern by treating the walls as an infinite potential barrier and the slit as a ...
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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 ...
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Why does light diffract when its light beam from a laser is directed at a hair?

Visible light has a short wavelength of 380-750 nm while a human hair range from 17 to 181µm (https://hypertextbook.com/facts/1999/BrianLey.shtml) what is many times larger that the wavelength of a ...
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Diffraction using a phone

I used my phone to create a diffraction pattern and measure the number of pixels along the horizontal. I used the formula in the picture and calculated everything using readings ive added in the ...
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Influence of monochromator entrance slit width on spectral bandwidth

I am working with a Czerny–Turner monchromator (a Bentham TMc300, to be precise), with adjustable entrance and exit slits. I started by acquiring the signal with the slits completely opened, and I got ...
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TEM diffraction analysis- imaging artifact or distorted crystal structure

I've got some "nanobeam" diffraction data from TEM (transmission electron microscope). Analysis is a challenging because I forgot the golden rule... I didn't measure a "standard". Hence, I don't know ...
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Difference between Airy disk and seeing disk

In the diffraction pattern for a circular aperture, instead of just having a circle, we have a central disk and several faint rings around the circle. Does the Airy disk consist of only the central ...
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What is the relation between difraction and energy levels?

Imagine I have an atom in the cold space. The energy gap between its current energy and the next is exactly equals to the photons energy that is about to meet an atom. Atom absorbs photon. All is fine,...
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How to reduce edge diffraction?

I have a simple setup with a diode laser and an object placed in front of it. I want to observe the edge's shadow clearly. However, I get this very annoying effect of diffraction and interference ...
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Diffraction grating produces two central maxima

I was performing a diffraction grating experiment using a grating spectrometer (shown in the picture) and noticed that at zeroth order there were two closely spaced images of the slit. The grating was ...
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Do neutrons that undergo diffraction lose or gain energy? And how much and in what form?

Neutrons that undergo diffraction change direction ... is there a change in the kinetic energy of that neutron? If so, how is that manifested?
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Bragg diffraction form an “inclined” crystal plane: which angle to consider?

Consider Bragg diffraction form an "inclined" crystal plane (i.e. not perpendicular to the normal of the crystal). I was sure that the angle of diffraction $\theta$ in bragg's law must always be ...
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Structure Factor for diffraction patterns

im trying to figure out myself the use of Structure Factor for Diffraction patterns. I have the Structure Factor for a monoatomic lattice $S(\overline G)=\sum_{i=1}^n f e^{\overline G \cdot \...
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Can Fresnel zone plates be used as collimators

I quite often use the principle in physics that (outside of thermodynamics), all laws of physics are time-reversible. And so, when looking at collimating microwave light, I though that it might be ...
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Diffraction at multiple slit [closed]

In multiple slit diffraction each slit contributes in diffraction phenomenon or only a single slit contributes in diffraction and all n contribute in interference?
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Comparison between X-ray diffraction and slit experiment

Most diagrams regarding X-ray diffraction suggest that after hitting an atom, X-ray would get reflected. But then the method results in an interference pattern which means X-ray get diffracted. I am ...
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Double Slit vs Diffraction Grating Intensity Graph

I had a few questions regarding the intensity graphs of fringe patterns observed when light is shone through a double slit vs a diffraction grating. For a double slit, does the intensity of the ...
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Why the effect of diffraction gets weaker as the distance between slits increases?

I was studying the light interference and I heard that in order to get a clear and fancy result the distance between slits has to be comparable to the wavelength not much bigger and I can't understand ...
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Fraunhofer's multiple slits versus atomic scatteres (diffraction)

I am currently busy with studying solid state physics and looking at diffraction theory. http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/mulslid.html#c3 explains Frauenhofer diffraction good. Let'...
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Using Miller indices to determine interference from a particular plane in a crystal lattice

In terms of x-ray diffraction from crystals. I was wondering how you can use the miller indices to determine whether there will be constructive or destructive interference from a particular plane in ...
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Arago spot on terrestrial object

Here is a question that occurred to me considering Fresnel's theory and Arago spot: Is there a bright spot on the surface of the moon in a lunar eclipse? If No Why? If Yes, have we ever make an ...
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What's a good textbook to learn about Diffraction in Optics?

I am taking a course in Fundamental of physics for Chemists, Below is the areas I want to learn Franhouofer diffraction Rectangular and circular apertures resolving power Single slit double slit ...
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How can I tell the cubic structure of different crystals?

So I have a couple of crystals I am analysing (LiF RbCl NaCl...) and I have the x ray diffraction patterns for them. How do I determine the different structures of these crystals as I need to ...