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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Neutron diffraction on Salty Ice VII

Can someone explain in layman's term how this figure shows the presence of Cl and Li ions in Ice VII ? What can we deduce about the crystal from this data ? The whole figure and caption are ...
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48 views

Seeing light source from its diffracted light

Even if the line of sight is blocked by something(like a wall as in figure) will I able to see the light source if I see the diffracted light of the source? 1.Will the observer no. 2 see the light ...
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33 views

How do you calculate the intensity of the $m$'th fringe in a Young's slits diffraction pattern? [on hold]

I'm preparing for an exam on wave optics and am struggling with part d) of this question: c) A beam of coherent monochromatic light (wavelength=500nm) is incident normally of a plane of two slits ...
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Diffractive peak for high-frequency scattering from a sphere with small index of refraction?

How does a transparent sphere's shadow fade as $n\to 1$? Consider radiation of wavenumber $k$ incident on a transparent sphere of radius $a$ and index of refraction $n$ in the limit $ka \gg 1$. ...
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1answer
37 views

Calculating wavelengths from angles in a diffraction grating? [on hold]

I am having some problems calculating wavelengths from some given information about a grating spectrum. A diffraction grating with a spacing of 3μm is used in a spectrometer to investigate the ...
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49 views

Why does fluorescence emission detector pick up second order wavelengths with first order scan, even though they have different angles?

my question in more detail and with an example: Let's say I have a 980nm laser and I use that laser to excite my fluorescent solution in cuvette. My scan range is from 300 to 800nm. If, for example I ...
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1answer
4k views

Fresnel half-period zone

I am following this set of lecture notes (see below). I understand that the idea is to evaluate the Fresnel integral for the circular aperture using the graphic method. However I don't understand at ...
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1answer
113 views

Single Slit Diffraction

I am trying to derive the intensity variation function for a single slit diffraction. Sorry for the poor diagram... So I decided to take the amplitudes of the waves originating from the slit on the ...
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1answer
22 views

Within what range of defocus from the object/image plane does the Fraunhoffer approximation hold?

The Fraunhoffer apporximation of diffraction is said to hold for an image "at infinity," or to be quantitative, for any observation point $R >> \frac{a^2}{\lambda}$. But it is said that, ...
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1answer
75 views

how can interference occur within diffraction?

My book says : The number of interference fringes occuring in the broad diffraction peak depends on the ratio d/a that is the ratio of the distance between the two slits to the width of a slit. In ...
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15 views

how the wavelength equation work? [closed]

today, my friend send me a question about diffraction and wavelength. A diffraction grating with 2000 lines per cm gives the second order fringe of a light at an angle of $12°28'$. Calculate the ...
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4answers
175 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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45 views

Explain Sun Glare

Above is a picture that I took just before the sun set. Notice the prominent red blob to the left of the sun. Can anyone explain the phenomenon that creates superimposed shapes and blobs in images ...
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1answer
207 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 ...
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1answer
47 views

X-ray diffraction: Is there an intuitive explanation of structure and form factors?

We have just started x-ray diffraction and I am utterly lost. We were given two formulas: First formula: The intensity of the x-rays scattered by $\mathbf{Q}=\mathbf{k}-\mathbf{k}'$ is given ...
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3answers
219 views

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
131 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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1answer
155 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 ...
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1answer
69 views

Diffraction wavelength relationship [closed]

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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2answers
107 views

Why the incessant confusion between diffraction and interference? [closed]

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
165 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) + ...
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1answer
27 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
40 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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1answer
238 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 ...
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676 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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1answer
40 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 ...
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1answer
256 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 ...
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24 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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21 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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2answers
69 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
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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16 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
28 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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62 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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87 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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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 ...
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1answer
54 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
65 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
50 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
24 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 ...
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3answers
186 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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3answers
506 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 .
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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
54 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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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
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1answer
87 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: ...
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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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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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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 ...