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 ...

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Why the incessant confusion between diffraction and interference? [on hold]

Feynman said, "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, important physical ...
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1answer
57 views

Diffraction wavelength relationship [on hold]

This question appears somewhat similar to other questions asking about why wavelength affects diffraction (a concept which I'm still not 100% sure on...) however my query is different and not answered ...
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45 views

Diffraction and wavelength [duplicate]

Why is it that when the slit-width is much larger compared to the wavelength of light, there is little diffraction or spreading-out of the light? And why is it that the diffraction effects are ...
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1answer
21 views

Actual spot size = geometric spot size + diffraction spot size?

I read in [1] that for a camera obscura the total spot diameter is equal to the diameter of the spot produced concerning geometric optics only plus the diameter of the spot concerning only ...
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1answer
31 views

What exactly is the reciprocal lattice and how is it connected to the Ewald sphere?

I want to understand what the reciprocal lattice is and how it is connected to the Ewald sphere. I know a very similar question has been asked on this site already: Reciprocal lattices. The top ...
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4answers
648 views

Which formula for the de Broglie wavelength of an electron is correct?

So, I have my exams in physics in a week, and upon reviewing I was confused by the explanation of de Broglie wavelength of electrons in my book. Firstly, they stated that the equation was: $\lambda = ...
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48 views

Single particle diffraction: how is this possible?

The intensity distribution of diffraction patterns are typically explained by looking at points of constructive and destructive interference of the diffracted waves on the detector. These diffracted ...
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0answers
22 views

Radial Distribution Function - Structure Factor relation, deriviation help

I'm attempting to prove the relation between the structure factor and the RDF, following the deriviation here (pg 92-94). The solution this source comes too disagrees with this paper which I trust ...
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48 views

Why half distance is taken?

Two towers on top of two hills are 40 km apart. The line joining them passes 50 m above a hill halfway between the towers. What is the longest wavelength of radio waves, which can be sent between the ...
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20 views

What is the relationship between the size of a slit and wavelength in diffraction? [duplicate]

Almost everywhere I see the statement that diffraction gets stronger when the size of the slit is comparable to the wavelength. I would just like to know the logic behind. Could anyone help me please? ...
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0answers
15 views

Producing a collimated beam from a point source

I have an optical fibre of numerical aperture $NA$, of very small core radius, located at the focal point ,$f$, of a lens. I should produce a collimated beam of initial radius $f\cdot NA$. But what ...
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1answer
25 views

Diffraction grating (finding number of emission lines)

I came across a question on isaacphysics.org where youre given information about a diffraction grating, the spacing of the gaps and the colour and location (in degrees) of 8 different maxima, of four ...
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0answers
21 views

Why isn't every magnetic neutron scattering peak a nuclear scattering peak as well?

Neutron diffraction is a well-established technique for determining the magnetic unit cell of magnetic materials. The idea is that nuclear scattering gives you peaks that correspond to the crystal ...
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2answers
60 views

Single slit diffraction - wave vs particle view

If monochromatic light is shot through a single slit onto a screen, we can analyze the pattern on the screen using wave properties. This analysis is done assuming the wavelength is constant. But with ...
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2answers
84 views

Can gravitational waves diffract off massive objects?

Can gravitational waves diffract off massive objects? If so, how much mass is needed to significantly disturb the waves propagation?
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1answer
50 views

Does this shadow diffraction effect have a name?

I noticed a cool diffraction effect today as I was sitting outside in bright sunshine: Suppose you have a fixed edge casting a shadow. If you put your hand on the side of the edge nearer to the ...
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2answers
61 views

What would diffraction of a macroscopic object look like?

I read an interesting question here in the forum (Will a football (soccer) diffract?) and came up with the following doubt: even though its diffraction angle is too small to be detected, if we had the ...
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1answer
39 views

Diffraction spikes using diffraction grating slide and white light

I recently completed an experiment using white light through both a circular aperture and four-piece diffraction slide at the same time. I'm trying to qualitatively explain what I'm seeing, which I ...
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1answer
22 views

Diffraction pattern from laser shone on coffe-filter plastered on glass pane

I make an ordinary coffe filter wet and plaster it on a glass pane. I then shine a laser onto the filter (on the side of the pane with the coffe filter). When I do this, I see what I assume is an ...
2
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0answers
33 views

Printing zone plate with laser printer

I tried to print my own zone plates on transparent plastic with laser printer with this generator. I prepared a lot of plates with different settings - focus from 4 to 60 cm, 3 wave lengths, etc. Yet ...
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1answer
46 views

Best collimation at focal point of lens?

From geometrical optics it is clear that we get the best collimation when the object lies at the focal point of the lens. I know that this carries over into cases where diffraction happens, but have ...
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0answers
31 views

Intersection point of two wires

When I observe two thin wires (up to 1cm, relatively) at a distance, if those two wires are intersecting (but may or may not have physical contact) the absolute point of their intersection is ...
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0answers
20 views

Slit width of a diffraction grating monochromator?

I am trying to find an equation for the bandpass of a diffraction grating monochromatic. I have found this source (link to google books) which indicates that it is given by: $$sD^{-1}$$ Where $s$ is ...
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0answers
20 views

Are k-points in the reciprocal lattice, points where constructive interference is the strongest?

I saw a video on youtube that seemed to imply that k-points are the positions where constructive interference is strongest. The link is https://www.youtube.com/watch?v=DFFU39A3fPY Is this true? I ...
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25 views

Structure Factor for a Simple BCC Lattice

This is an example of a general misunderstanding I am having. The structure factor is given by $$S=\sum_{j}f_je^{i\mathbf{G}.\mathbf{x_j}}$$ where the index $j$ denotes a sum over the atoms within a ...
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2answers
78 views

Why do electromagnetic waves diffract? [duplicate]

The expansion of electromagnetic waves due to diffraction can be easily explained with Huygens' principle (and in introductory courses this is usually how it is explained). But Huygens' principle is ...
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1answer
45 views

Is it possible to see a diffraction pattern from a BCC crystal made of 2 randomly-distributed species?

Suppose I have a 50-50 mix of two different kinds of atoms in a crystal. The crystal is BCC and the atoms have different scattering factors $f$. I know that if the crystal is organized in the regular ...
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1answer
87 views

single slit diffraction - $\sin\theta=n(\lambda)/b $ or $\sin\theta = (2n+1)(\lambda)/b$

I'm getting a contradiction as follows and am not sure how to resolve it: logic 1 leads to the conclusion that the higher order minimas of single slit diffraction will be given by $b\sin\theta = ...
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0answers
30 views

Using Fraunhofer diffraction when projecting on a curved screen

Suppose I have a slit very far away from a curved screen (suppose part of a circle). If the screen was flat, the far field approximation is due to the Fraunhofer diffraction, and is given by $$ ...
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0answers
50 views

Laser shone at liquid jet

When a liquid jet of water falls in laminar flow, it hits a surface. If this contact point, between the surface and the jet, is illuminated by a laser. Rings of light can be seen forming around the ...
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1answer
101 views
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Fraunhofer diffraction contradiction

Assume two obstacles are complementary. For example, a circular aperture and a circular stop of same radii. My theoretical analysis leads to contradictory conclusions about such situations. 1) ...
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1answer
151 views

Young's Double Slit - Number of Fringes

A double slit is illuminated normally with coherent light. An interference pattern is observed on a screen. The width of both slits in the double slit arrangement is increased without altering the ...
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1answer
49 views

Reflective angles from a CD [closed]

How do I estimate the diffraction angles of laser light which illuminates a CD? Does the storage capacity have an impact? Theories I have considered are: refraction diffraction $\sin(\theta)=\frac ...
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1answer
48 views

what does d spacing between planes in a crystal lattice mean?

I have trouble understanding the meaning of d-spacing. d spacing is supposed to give the interplanar distance. for a cubic lattice $$d_{hk \ell}= \frac {a} { \sqrt{h^2 + k^2 + \ell ^2} } $$ What i ...
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1answer
222 views

Why is my shadow deformed and not the shadow of the ceiling? [duplicate]

Look at these two photos of my shadow from sunlight. Case 1: My shadow is separated from the shadow of the ceiling and my head is round. Case 2: But when I walk a little more and the shadow of my ...
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3answers
171 views

Single slit diffraction - choosing a wavelength?

For the classic experiment of determining the slit width of a single slit. If we assume the rough order of magnitude of the width is known. What factors determine the choice of wavelength? (Clearly ...
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1answer
27 views

Diffraction of light and separation of its colors

When the wave fronts of light pass through a barrier that has many slits, different wavelengths appear at different angles. What I don't understand is that why is it when the angle changes so does the ...
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1answer
54 views

Will smoke affect young's double slit experiment

If smoke is present in between the screen and slit in Young's double slit experiment using laser, will there be any change in the interference pattern? Will the fringes be obtained on the screen? ...
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3answers
61 views

Bending of light [closed]

Why does bending of light(diffraction) occur?
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1answer
31 views

Why does Diffracted Light cone diameter change in relation to angle of light beam?

I have a question about light diffraction. Take a look at these images of the Pantheon oculus. Now what I don't understand, in the first picture, the light is coming in from overhead and forms a ...
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1answer
146 views

How to calculate a straight edge diffraction pattern

A straight edge diffraction pattern is not the same as a slit or multiple slit diffraction pattern. The spacing between fringes is not equal but gradually gets smaller the farther out you go as in the ...
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0answers
30 views

Wavelength limited resolution

I've read through answers to similar questions, and I haven't been able to find a satisfying answer. I've heard it said that in order to make out something, you need to use light with a wavelength at ...
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1answer
110 views

Total number of primary maxima in diffraction grating

I am trying to determine the total number of primary maxima that can be observed when light of wavelength 500 nm is incident normally on a diffraction grating, with the third-order maximum of the ...
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0answers
57 views

Single Slit/Double Slit path differences

When diffracting light through a double slit, I understand that the two sources must arrive on the screen m(wavelengths) out of phase [where m is any whole number], in order for a bright fringe to ...
1
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1answer
42 views

Does the wavefront in the double slit experiment represent the electric field of the EM radiation / light?

The question "What is a wavefront?" get the answer "A wavefront is a contiguous region of constant phase". This seems to be right for water waves as well as for electromagnetic radiation. But what is ...
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2answers
65 views

Are wave fronts in double-slit experiments moving forward? [closed]

I ask a question about "What is a wavefront?" which follows the question "What makes the radiation behind a slit coherent". For the wavefront it was answered, that "In electromagnetics ...(that are) ...
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0answers
87 views

Question about heisenberg uncertainty principle and single-slit diffraction

My question relates to this video illustrating the Heisenberg uncertainty principle. The video shows light being shot through a slit forming a spot on a screen. As the slit narrows, the width of the ...
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3answers
89 views

What is a wavefront?

For this picture Anna wrote: "Incandescent light is incoherent because it comes from many sources and the same is true for sunlight. By passing the light through the one slit he created a single ...
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2answers
95 views

What makes the radiation behind slits coherent?

Have a look on the sketch To get such a intensity distribution of light behind a slit we presuppose that all the light that moves on the two lines is coherent; of the same wavelength AND the same ...
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1answer
33 views

Monochromatic light and interference [duplicate]

What I want to ask is monochromatic light necessary for interference? Doesn't interference occur on just the superposition of two waves(any waves)? And Why don't waves of different wavelengths don't ...