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 evidence for electrons interfering with each other, not just themselves?

When electrons are passed one by one through a double slit experiment a diffraction pattern forms over time. As far as I can tell the same pattern forms if a beam of electrons is passed through the ...
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Understand Spatial light modulator (SLM)

Spatial light modulator (SLM) is a general term describing devices that are used to modulate amplitude, phase, or polarization of light waves in space and time. Spatial Light Modulators (SLMs) employ ...
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How precise must corner reflectors be to render satellite megaconstellations effectively invisible to astronomers?

With the emerging environmental concerns over light pollution from satellite megaconstellations, getting a quantitative estimate of the magnitudes of various approaches to minimizing the pollution ...
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Can we build Fresnel lens for neutrinos?

Suppose we know neutrino mass and speed. This makes us know it's de Broglie wavelength in vacuum. Now suppose it is travelling through matter filled by some "atoms" with concentration $n$ ...
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Why doesn't the explanation for the destructive interference in single slit diffraction also apply to constructive interference?

The explanation for the single slit diffraction pattern is that when a ray at the top and a ray at the center of the slit, at $\frac{b}{2}$ where $b$ is the slit width, marked by red in the left ...
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Effect of a cylindrical lens in front of a diffractive optical element (DOE) and 5mW red laser

I want to expand the image formed by a grid pattern diffractive optical element (DOE). I will be using a 5mW red (650nm) laser. I thought maybe putting a cylindrical lens in front might spread the ...
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Kirchhoff Diffraction for backwards wave propagation

Classic Kirchhoff Diffraction integral for a monochromatic wave is formulated with a restriction that it's only applicable to a point that's outside of the volume enclosed by the integration surface ...
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Centrosymmetry in diffraction glasses

I recently purchased quirky diffraction glasses and when looking at the sun or any source of light I noticed that there is ​centrosymmetry. ​​​​ What is this due to, perhaps the conservation of ...
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What does Fraunhofer diffraction around a circular shadow look like?

I want to combine the set-ups of the Arago spot (small disk in the light path, diffraction pattern imaged directly behind it) with the set-up of the Airy disk (small aperture in the light path, ...
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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 ...
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Would being nearsighted/astigmatic lead to seeing diffraction patterns from white light?

I am nearsighted with a prescription of greater than -10 diopters and an astigmatism. When I take off my glasses or contacts and look at a source of white light such as a lamp, then I observe white ...
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Does a lens always act as a Fourier transform?

I understand that putting a lens behind an aperture at the distance 1f, it will "get" the diffraction pattern to appear in the back focal plane. In this case the FT of the aperture plane ...
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Divergence of a laser beam due to diffraction

during Introduction to Photonics course my lecturer used a formula to calculate the angle by which the beam diffracts as $\theta=arcsin(\frac{\lambda}{2d})$ where d is the width of the aperture. My ...
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Angular dispersion of a diffraction grating

I am not sure what is '$a$' according to the angular dispersion formula below. The formula is $$ \frac{d\theta}{d\lambda}=\frac{m}{a\cos\theta} $$ Is it the distance between two consecutive slits?
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Fraunhofer diffraction and lens

[This image is collected from the Fraunhofer diffraction article of wikipedia] Fraunhofer diffraction and lenses In Fraunhofer diffraction the source is infinitely away from the lens and screen which ...
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Littrow config angle of dispersion discrepancy

Littrow config angle of dispersion discrepancy I can't seem to get my hand calculations to match ray-trace simulations. My angular dispersion is larger by a factor of ~2 in my simulation (I am using a ...
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Is a pulsar EM-radiation affected by diffraction?

Is a pulsar EM-radiation affected by diffraction? As I understand gaussean beam theory there should exist different diffraction or if You want diffusion angles for different wavelengths, for example ...
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Introducing two different slabs in Young's double slit experiment

Suppose there are two slabs of refractive indices $n_1$ and $n_2$ kept in front of the sources of light with wavelength λ as shown, how do we calculate the distance of the first bright fringe from the ...
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Single slit of diffraction with increased width of slit

Question in brief : Why increased width of slit makes single slit diffraction almost unobservable? Question in broad : I was going through my textbook and found that diffraction cannot be observed if ...
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Diffraction Grating question/s

I wrote a little program to model a diffraction grating: Does a photon go thru every slit, or just a few, in an inch/es wide DG!? Do I treat a slit as just a single point source? Does a photon ...
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Why does diffraction happen in cases like these?

Diffraction, at least as its commonly explained, happens when light crosses an obstacle "of size in the same order as its wavelength". For example, a small slit. However, in one of my labs, ...
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Effect of finite width of source slit, diffraction?

I am studying Fraunhofer diffraction on Jenkins And White Fundamentals of Optics. The apparatus is and in one chapter he considered $S'$ of finite width and they consider two source points $P$ and $...
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Does it makes sense to interpret the Point Spread Function as a volumetric density of energy?

The Point Spread Function (PSF) of an imaging system is its impulse response. Therefore $$ I(x,y,z) = \left[O \star PSF\right](x,y,z) $$ where $I$ is the image, $O$ is the object, and $\star$ is the ...
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Diffraction grating of light

Although I could understand the basics of single slit diffraction, diffraction grating seems something confusing to me. In diffraction grating, we know there are a lot of slits within a unit length. ...
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Is there a difference between a diffraction pattern and an interference pattern?

I am in high school at the moment and I am revising a section on waves. I am slightly confused by some things in our notes, which I would like to ask about. We looked at Young’s double slit experiment,...
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How does diffraction affect the amplitude of sound?

Let’s say we have a 2D “maze” which represents walls in a space. If we place a sound source somewhere in it, what would be the amplitude at a different point in the maze. Or in a simpler case, given a ...
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Why sun rays are parallel not of stars?

I have studied that when a light enters from space into earth atmosphere it experience atmospheric refraction many time due to different atmospheric layer. Then why we take sun rays parallel? They ...
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What is the explanation for bright lines in light-diffraction by a straight edge?

I’m just studying diffraction by a straight edge. I did not find any explanation for the origin of the bright lines l' and l". The line l' is visible in relation to the laser beam at an angle &...
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Diffraction physics v. parageometric optics, whatever happened to it?

In 1950, Giuliano Toraldo di Francia published a paper [1] with the title "Parageometrical Optics" followed by several other papers on the subject, I dare say culminating in a beautiful ...
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Why do we observe the difference in the intensity pattern of Interference and Diffraction?

As well said by Richard Feynman, “No one has ever been able to define the difference between interference and diffraction satisfactorily. It is just a question of usage, and there is no specific, ...
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Dimensions of a Double Slit Diffraction Grating [closed]

The first minima of the sinc function of a double slit diffraction grating can be found at $\theta = \pm 0.1^\circ$. For incident light at $\lambda = 400nm$ I am trying to find the dimensions $a$ and $...
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Phase difference for waves propagate through an aperture

Consider a system where waves propagated through an aperture with a size of $a$. The variations of the phase $\phi$ from the points the edges is given by: $$ \Delta \phi = k ( d_{\text{edge2}} - d_{\...
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Phase difference approximation

I'm sitting and trying to solve the equation of the phase difference given by: $\Delta \phi = k (\sqrt{a^2+d^2} -d) \approx \frac{ka^2}{2d}$ Where $a$ is the size of an aperture and $b$ is the ...
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Single slit diffraction angle between maxima

Lets say we have a certain wavelength $\lambda$ and a known slit width $d$, how can I calculate (approximately) the angle $\theta$ between the central maxima and the next maxima? I know that $d \sin \...
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What's limiting the field of view of a lens

An ideal lens with finite aperture leads to the formation of an image in the image plane as \begin{equation}g(x, y) = \int \text{psf}(x/\lambda d - x', y/\lambda d -y') f(x', y') dx'dy',\end{equation} ...
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Do free electrons in a crystal reflect off lattice planes?

My textbook (Arthur Beiser Intro to Modern Physics) states that "unbound low-energy electrons can travel freely through a crystal since their waves are long relative to the lattice spacing $a$ &...
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Double slit interference question a level physics [closed]

The question attached asks you to calculate the angle between the central fringe and the second bright fringe. The mark scheme says that you should use tan to work out this angle using the distance ...
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Distance between diffraction minima for electrons and muons

I want to find the distance $l$ between the diffraction minima on either side of the central peak for a)100 eV electrons passing through a slit of width $w= 1 \mu m$, at a distance $d$ of 1 m. b)100 ...
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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 ...
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Complex transmission coefficients for unpolarized light

My goal is to use a diffraction integral for an optical wave that has traversed a component for which amplitude transmission coefficients for s and p polarized light are known. However, I am a bit ...
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What is the minimal size the slit should have in order for an interference pattern to occur? [closed]

Consider the single slit experiment. The width of the slit can be given as: $b= \frac{\lambda}{2} * \frac {1}{\sin(\theta)} $, where $\theta$ is the angle for the first minimum is. At which minimal ...
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Numercial simulation of the double slit experiment

Originally I had a code that simulates single slit diffraction: parameters for functions: ...
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In diffraction from a metal ruler, why can more orders be seen above the central bright spot than below?

Looking at the attached image, why are there not as many orders under the 0th compared to above?
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How does diffraction cause laser beam divergence, and why will a laser beam always diverge, due to diffraction?

I have seen it said that diffraction causes laser beam divergence, or that a laser beam will always diverge, due to diffraction, or some variation of these statements. I understand diffraction in ...
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Three patterns on DVD grating

Recently, I attempted to use my DVD as a reflective diffraction grating. The setup is shown below: a green laser is shone on the DVD, and the diffraction pattern is shown on the wall. However, in one ...
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Is redshift acting on pulses from pulsars and how it changes the diffraction of the pulse and so its brightness?

Is redshift acting on pulses from pulsars and how it changes the diffraction of the pulse and so its brightness? As far as I know the diffraction becomes higher while wavelength increases as moving ...
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In Fourier Optics, does the distance between a lens and a diffraction apparatus have an impact on the shape of fringes?

In our optics lectures we were given the following explanation as to how to deal with a lens as a fourier element: We are told that to find the intensity function of the diffracted light, we first ...
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Why do we need collimated light on a diffraction grating?

In all of the images I've seen from a spectrometer, there's always a collimating element that places an image at infinity so as to have parallel rays hitting a diffraction grating. But why do we need ...
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Constructive interference in single slit diffraction

Double slit diffraction seems to be easier to understand than single slit diffraction, in which the single slit are thought to be wider, therefore multiple sources of semi circular waves are present ...
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How to set up the right model for solving diffraction numerically?

The diffraction of waves in free space is governed by the sourceless Helmholtz equation $$\nabla^2u +k^2u=0$$ There is a well stablished solution called Kirchhoff´s diffraction integral (KDI) and it´...

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