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 ...

learn more… | top users | synonyms

0
votes
1answer
109 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 ...
6
votes
1answer
91 views
+50

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) ...
3
votes
1answer
145 views

Diffraction pattern without a slit

A few weeks ago, I aimed a laser at a wire perpendicular and interestingly, I saw the diffraction pattern, like the picture below: Why is this happening? I mean, I don't have any slits and I'm ...
1
vote
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 ...
1
vote
2answers
93 views

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 ...
-2
votes
0answers
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 ...
0
votes
1answer
163 views

Path Difference Due to Angled Incident Light

If light incident on a diffraction grating makes an angle $\alpha$ with respect to the normal to the grating, show how $$m \lambda = d\sin\theta$$ becomes $$m\lambda = d[\sin(\theta - \alpha) + ...
1
vote
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 ...
2
votes
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 ...
1
vote
1answer
216 views

Why water wave won't diffract or bend around a boat having a length longer than its wavelength?

I get the slit version of diffraction, with the Huygen's principle. But I don't find the same principle useful. I keep thinking that a obstacle like a boat is the same as two large slits on both ...
8
votes
4answers
642 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 = ...
2
votes
1answer
38 views

Does the Abbe limit hold for a single lens?

Let us say I have a single (converging lens) could I use the Abbe diffraction limit (for a microscope) to find its resolution or do I have to use the Rayleigh criterion. (i.e. Is the Abbe diffraction ...
1
vote
0answers
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 ...
0
votes
1answer
247 views

Slit width for minimum spot size in electron slit diffraction if involving uncertainity principle

I don't believe the following is an accurate description of the physical but a homework problem to help understanding. A beam of electron of energy 0.025 eV moving along x-direction, passes ...
0
votes
0answers
27 views

what happens to light when it passes through a magnetic field of infinite feild strength? [closed]

Light has both particle and wave nature.If light is to be considered as a particle what happens to light when it is passed through a media of infinite magnetic intensity and infinite field ...
1
vote
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 ...
-1
votes
0answers
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 ...
0
votes
0answers
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? ...
1
vote
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) ...
1
vote
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 ...
0
votes
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 ...
1
vote
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 ...
0
votes
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 ...
2
votes
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?
5
votes
4answers
851 views

Why does light diffract only through slits?

We can see diffraction of light if we allow light to pass through a slit, but why doesn't diffraction occur if we obstruct light using some other object, say a block? Why are shadows formed? Why ...
4
votes
1answer
200 views

Diffraction and $k$-space

Regarding diffraction I am a little bit lost reading about reciprocal space and the space of $k$'s. As I understand it the Fourier relationship between a wavepacket $\Psi(\vec r,t)$ and the complex ...
1
vote
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 ...
1
vote
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 ...
0
votes
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 ...
1
vote
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
votes
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 ...
0
votes
3answers
445 views

Why does sound wave suffer more diffraction than light waves generally?

Why do sound waves suffer more diffraction than light waves generally ? I would like more of a logical explanation rather than mathematical .
2
votes
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 ...
1
vote
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 ...
2
votes
3answers
1k views

Newton's rings experiment

I have performed experiments in my college laboratory on Newton's rings to find radius the of curvature of the convex lens used. I always get a dark center. Is it possible to get a bright center? If ...
4
votes
1answer
82 views

Beating the Diffraction Limit with NSOM

I am trying to understand exactly why we can beat the diffraction limit when using near-field scanning optical microscopy (NSOM). For those who aren't familiar with NSOM, check out this article: ...
1
vote
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 ...
0
votes
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 ...
0
votes
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 ...
8
votes
6answers
3k views

Why does a wave actually diffract?

I know that waves diffract around a slit and this is due to the Huygens-Fresnel principle. But I never understand this in an intuitive wave that why does a wave become a spherical wave front at the ...
0
votes
2answers
77 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 ...
1
vote
0answers
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 ...
0
votes
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 ...
0
votes
1answer
86 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 = ...
1
vote
1answer
45 views

Process of x-ray crystallography

This is a pretty basic question but I would just like some confirmation of what I suspect is true. As I understand it, the basic idea behind x-ray crystallography is that we take our crystal and hit ...
0
votes
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 $$ ...
0
votes
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 ...
0
votes
1answer
149 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 ...
1
vote
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 ...
8
votes
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 ...