# 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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### Why does the flux as a function of the selected energy of the simulated data not resemble the experimental flux?

I(with the help of my colleague) have used a Monte Carlo simulation software called McXtrace to simulate crystal diffraction glitches. Glitches occur when, for a specific energy, the Bragg law is ...
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### Are intramolecular correlations observed in small-angle scattering?

In small-angle neutron or x-ray scattering, the total scattered intensity $I(Q)$ is proportional to $$I(Q) \approx P(Q)S(Q)$$ where $P(Q)$ is the form factor, and $S(Q)$ is the structure factor. Small-...
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### Error analysis in measuring wavelength using diffraction grating [closed]

If $\alpha_m$ are the diffraction angles where the diffracted wave has maxima, then the wavelength is given by the following $$d\sin{\alpha_m} = m\lambda.$$ In order to find $\lambda$, I've run a ...
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### Can the human eye see the images of 300 nm light on a screen through a diffraction grating?

In my textbook there is a question as follows: A diffraction grating with 200 lines per mm is placed between a monochromatic light source and a screen. The distance from the grating to the screen is 2....
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### Effect of thickening polariser on intensity pattern

I've performed an experiment where microwaves were sent through a polariser of varying thickness, composed of $11$ slits (width and spacing both $6$ mm). To vary the thickness of the polariser, this ...
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### Kitchen experiment with a laser distance meter

I'm performing a kitchen experiment where a knife's blade is placed in the path of a laser distance meter(red light). At a distance of around 40cm I'm able to get distance readings that are smaller by ...
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### Intensity as a function of selected energy by a crystal monochromator simulation data is different from experimental data

As explained in the above, with a ray tracing Monte carlo simulation software, I record the intensity as a function of the energy I chose to select with a crystal monochromator after the beam has been ...
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### Do the photons from 43 attosecond pulse lasers produce double-slit diffraction patterns?

Laser pulses have been produced at the range of 43 attoseconds. If I'm doing my arithmetic correctly, this represents 12.9 nanometers at the speed of light. And, if I'm understanding the link ...
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### What is the physical meaning of two solutions of grating solutions for $m=0$?

I was confused by how Feynman defined the angle of input and output. I thought it is regular reflection when input angle equals output angle where it is the first situation in Feynman’s description. ...
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### Is this an accidental interference pattern?

I recently purchased this laser level. When I turned it on, I got excited when I noticed that it projected this interesting pattern on the wall: Is this an interference pattern? I don't know much ...
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### Can someone explain the equation used to calculate the nuclear diameter/radius using electron diffraction? [duplicate]

It seems as though the equation here ($d\sinθ=1.22\lambda$) is more or less the same as the equation for diffraction gratings ($d\sinθ=n\lambda$). However, in the equation for the gratings, d is the ...
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### Order of Diffraction Bragg's law

Given the relation of Bragg's law $\sin\theta= \frac{n\lambda}{2d}$, this suggests that for a given wavelength $\lambda$ the order of diffraction is limited such that $\sin\theta$ is less than one. ...
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### Why is Copper ($\rm Cu$) better than Molybdenum anode for X-Ray diffraction?

I work in a physics lab, and the project I am working on includes X-Ray (Bragg) diffraction using $\rm NaCl$ single crystal and powdered sample. My professor said that changing the anode of the X-Ray ...
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### Why does yellow light shining on the tv diffract all spectrum of light?

This was an image I took during the evening time on the led tv , I had two questions the first was why was the tv giving off a x pattern of the diffracted light which constitutes primary white light ...
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### Relation between Fourier transforms and atomic form factors

I am currently trying to understand how the X-ray diffraction pattern relates to the Fourier transform of the atomic electron density function. I roughly understand the theory behind the diffraction ...
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### Optics question: Simple way to transform a parallel bundle of collimated beamlets into a converging (diverging) bundle of collimated beamlets?

I'm searching for an optical element that converts a parallel bundle of individually collimated beamlets into a converging or diverging bundle of still collimated beamlets (or vice versa). So ...
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### Why does an electron diffraction pattern of a crystal come out to be visible in the reciprocal space?

I have been recently trying to understand electron diffraction patterns of crystals. What I am not able to visualise is the reason why a diffraction pattern of the reciprocal space is formed on the ...
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### Number of Possible Primitive Vectors and Primitive cells in a Bravais Lattice

According to my Book Solid State Physics by Ashcroft and Mermin, given a 3-dimensional Bravais lattice, there are infinite sets of 3 primitive vectors that we can come up with that will span the ...
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### In an optical system, does the Point Spread Function apply to all light? Or only Point light sources?

So in optics, the Point Spread Function (PSF) describes how an optical system responds to a point source of light. My understanding is that this is due to diffraction and the wave-like nature of ...
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### Radius of bands in single slit diffraction

We've been given the following situation: the cylindrical tube is of radius r and length l and is covered with an opaque disc having a small hole in the center on the left end and a point light source ...
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### Is it possible to measure the temperature of a candle by the diffraction method?

I am reading a book " Physics, Fun and Beyond" by Eduardo de Campos Valadares. In his book, he is mentioning about an experiment "bending laser beams with hot air." I am posting a ...
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### If $I$ is the intensity of the principal maximum in the single slit diffraction pattern, then what will be its intensity if the slit width is doubled?

I've found a few results on the internet for this question, all with different explanations or different answers. Some say it'll become 4I and some that it'll not change. I see that there are a few ...
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### Why does Bragg's law consider only specular scattering for constructive interference?

My textbook only considers two-dimensional scattering, so I will stick to that. When explaining Bragg's law, it states that the incidence angle and the scattering angle must be equal so that all ...
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### Diffraction of a laser composed of 2 monochromatic colours through a single slit / $N$ slits

To make the example simple, let's say we have a yellow laser that is the combination of 2 monochromatic lasers (green + red). In the example I will give, let's consider that the slits are narrow ...
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### Young slits, are interferences possible without diffraction?

Is it possible to have a Young experiment with N slits producing interferences but no diffraction? In my course, we have two formula's for the intensity at a certain point after the slits: one for ...
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### Single slit diffraction vs conservation of momentum [duplicate]

I'm reading: "What Is Real?" by Adam Becker, book mentioned Einstein's thought experiment: At that 1927 conference Einstein made a short presentation during the general discussion session ...
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### Understanding the Static Structure Factor of a Liquid

I am trying to understand static structure factors, $S(Q)$, for liquids. This function represents pairwise correlations in reciprocal space and can be measured experimentally using X-ray or neutron ...
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### Deducing specific hkl directions from families of hkl directions

For a crystal I have families of equivalent directions < > and I'm trying to deduce specific directions. The family of the main plane of diffraction of the crystal is <111>. <110> is ...
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### Resolving power of a diffraction grating

For a experiment we have measured the wavelengths of the spectrallines corresponding to a sodium lamp. We have also measured the splitting distance, most likely to happen due to spin-orbit coupling, ...
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### Fastest most accurate orientation measurement of an object while intermediary objects are involved to pass relative information

I am looking for the fastest most accurate way to have the orientation of an object measured optically while intermediary objects are involved between the source and the target. An example scenario ...
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### Momentum transfer to dielectric thin slit array grating

I know that when light impinges on a planar slit array grating (say, dielectric transmission grating, equidistant slits), the light diffracts and breaks into orders. If the light changes its momentum ...
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The form factor in x-ray scattering is defined by $$P(\mathbf{q})=\left [ \frac{1}{V_{p}} \int_{V_{p}} dV \exp(-i\mathbf{q}\cdot\mathbf{r})\right ]^{2}$$ For a sphere, this becomes $$P(q)=\left [ \... • 520 -1 votes 1 answer 54 views ### Uncertainty principle - single slit diffraction - one particle In reference to this diagram: http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/sinslit.html Let x be the horizontal axis and y be the vertical axis. We make the slit width arbitrarily small. Assume ... • 1,186 0 votes 0 answers 59 views ### Why reflection occurs in crystals? Why do reflections occur in crystals? Why not transmission only? How can atomic planes work as mirrors? • 71 0 votes 1 answer 176 views ### What is \Delta x in Heisenberg principle for a single slit? In the diffraction from a single slit a particle goes tru the slit of size D. Is the \Delta x in HUP \Delta x~\Delta p>h equal to D? Please give a QM pdf book where it is said plainly. I ... • 584 1 vote 0 answers 31 views ### Why doesn't a pinhole camera result in blurred images due to diffraction? Shouldn't a pinhole camera image be super blurry due to diffraction? Why does it work? • 1,267 0 votes 0 answers 59 views ### Diffraction through fingers I found two different versions of single slit diffraction through fingers here and here (12th slide). Which one is correct? I think there will be a spike perpendicular to the gap as in the first one ... • 299 0 votes 0 answers 16 views ### Understanding implications and differences between ray-based diffraction models I have been researching ways to model a measured signal while taking diffraction into account. Interestingly, I found that diffraction can, in principle, be modelled with rays, although they need to ... • 25 2 votes 0 answers 49 views ### The fundamental relation between interference and diffraction [duplicate] high schooler here.i was not convinced by the validity of the huygens secondary wavelets hypothesis and beleived that both interference and diffraction should arise from the simple wave equation A=... 1 vote 2 answers 82 views ### Can the colors of white light be separated through reflection alone? Can the colors of white light be separated through reflection alone? My answer to this is no since if we want to separate the colors, we use prism and when light passes through a prism, the dispersion ... • 11 0 votes 2 answers 57 views ### Stellate spikes around luminous objects Why do bright objects feature a stellate around them (like in the lights on the bridges below)? If this were due to scattering of light, I'd have expected it to be like a luminous sphere around rather ... • 299 0 votes 1 answer 53 views ### Diffraction limit for a square aperture? I know that for a circle it is 1.22 lambda/D, which gives a result in radians. What is the equivalent for a square aperture? I seem to vaguely remember that it is the same but drops the 1.22, but I ... • 203 0 votes 1 answer 45 views ### Why has this pattern formed in a photo of my laptop screen, and why does it vary from camera to camera? [duplicate] So I got these weird patterns when I photographed my laptop screen with a phone camera (Realme Narzo 10A). I thought they might have something to do with diffraction. Then, for some reason, when I ... • 472 0 votes 1 answer 61 views ### Non-fundamental interactions that are yet to be explained I was trying to understand some of the non-fundamental interactions in physics. I stress non-fundamental, because I am a student of particle physics and in the first semester of the master's we have ... • 119 1 vote 0 answers 61 views ### Why are stars portrayed to have pointed corners even when they emit light in every direction Is it just for representative purpose or does it have any meaning 0 votes 0 answers 38 views ### Questions about creating diffraction grating I have a modern physics lab project this semester where we have to perform an experiment related to modern physics as a group of 3. We choose https://aapt.scitation.org/doi/10.1119/1.5020051, an ... • 193 4 votes 1 answer 147 views ### Phase shift in diffraction I am studying the derivation of the Fresnel-Kirchhoff integral. It puzzles me that one of the conditions imposed is a phase shift of \pi/2 between the incident and diffracted wave. Where does this ... 0 votes 0 answers 44 views ### What is a physical explanation of scattering vector q? I understand that q = 4 \pi \sin\theta\,/\lambda in scattering theory. Also, q = 2 \pi/k, where k is the wave vector. I have read the explanations that it is the momentum vector, the scattering ... 0 votes 0 answers 33 views ### Understanding diffraction using Uncertainty Principle When light falls on a slit, I can take the width of the slit as the maximum uncertainty in position of the photons as they pass through the slit. So I know \Delta x (direction x is perpendicular ... • 645 1 vote 1 answer 32 views ### Finding width of a slit in diffraction 500nm light is illuminating an aperture of width$$d_1=0.2mm The diffracted light from this first aperture then illuminates a second aperture $1m$ away. What is the smallest width, $d_2$, of the ... 