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4
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1answer
213 views

Diffraction Pattern on LCD Screen

I was up late working with my red LED headlamp on and when I was looking at the black part of my LCD (Apple Retina Macbook Pro) screen I noticed this interesting diffraction pattern. I'm confused ...
0
votes
2answers
31 views

What should be the width of the slit in single slit diffraction experiment?

What should be the width of the slit in single slit diffraction experiment? If the wavelength is taken lambda while doing experiment.
0
votes
0answers
32 views

Highest NA available [closed]

I am curious, what is the highest NA for an objective available now? Most of the manufactures offer something like ~1.4 (for immersion objectives), but I think about half a year ago I heard someone ...
0
votes
0answers
29 views

Intensity of waves in single-slit diffraction

So I am trying to determine the relation between intensities of waves in single slit diffraction. Since I am pretty new to this topic, I couldn't find a way how to calculate the ratio between the ...
3
votes
1answer
45 views

How can diffraction happen in the Hubble Telescope?

I've seen people talking about the angular resolution of the HST is, if using Rayleigh's criterion, equal to: $$\theta = 1.220 \frac{\lambda}{D}$$ My question is, since the diameter of the HST $D$ ...
0
votes
1answer
28 views

How do I interpret the math relating to diffraction?

The following is a quote from the Haifa Lectures (Mendel Sachs) But if both slits are open, the wave function for the electron penetrating screen S1 is the superposition of states, $(\psi_1 + ...
0
votes
2answers
19 views

What is an off-axis peak in x-ray diffractometry?

I'm looking at a $\theta$ - 2$\theta$ pattern of my thin film which in bulk is cubic (bcc) and I see 001 and 002 peaks of the film. There is supposed to be a tetragonal distortion meaning that I need ...
5
votes
0answers
159 views

Why is this way of calculating the diffraction pattern valid?

I've seen that in some books (Fowles) the intensity of the diffraction pattern is calculated in the following way. We place the source $S$ and the point at the screen $P$ in the line perpendicular ...
1
vote
0answers
27 views

Can I calculate the form of the aperture from the diffraction pattern?

As I understand, the Fraunhofer diffraction pattern of light is the Fourier transform of the aperture. More precisely, the amplitude of light would be the Fourier transform and the intensity its ...
0
votes
1answer
33 views

Diffraction grating problem [closed]

We have 8 slits, each separated from its neighbour by $ 0.05$mm. We use light of wavelength $576$nm. The problem is to calculate at what angle the first minimum occurs. The answer is given: ...
-1
votes
0answers
27 views

Fresnel to Fraunhofer limit

I'm puzzled about what happens when distance L from obstacle to screen is continuously increased from a small value (Fresnel diffraction) to infinity (Fraunhofer diffraction). Please consider four ...
0
votes
1answer
33 views

Simulating of Fraunhofer Diffraction of Zigzags by FFT

I tried to study the diffraction pattern of the following zigzag grating by Matlab(FFT of this image).. And the result showed like this(please ignore the scale bar in this img) I think the ...
6
votes
1answer
319 views

Self-Accelerating wavepackets: What are they and can they impulse a spaceship?

Nature today published a (paywalled) article that mentions 'Self-accelerating Dirac wavepackets'. They claim that they behave in a similar fashion as the diffractive tricks of polarized beams that ...
1
vote
1answer
71 views

Basic rule for diffraction

I'm a high school student. I still don't understand the reflection, diffraction and refraction of light. It seems to me that in concept of quantum physics, reflection is just a process of object ...
0
votes
0answers
11 views

How do I derive Sommerfeld's solution of the case when the incident ray is aimed obliquely to the edge of the screen?

I already know that the Sommerfeld's solution to this problem is conical. But internet does not show me the simple of exact derivation of this solution. How do I solve this problem?
0
votes
0answers
42 views

Huygens and philosophy of the slit

A single (narrow) slit diffraction pattern, can be explained/described classically with Huygens' principle (1678), and quantum mechanically with the Uncertainty principle. If the pattern on the screen ...
9
votes
2answers
190 views

Wavelength used in manufacturing of integrated circuits (IC)

How is it that the silicon ICs industry can burn ICs of a dozen nanometers using photolytography with UV laser of about 193 nanometers? Since the gates are smaller than the wavelength, for example ...
2
votes
3answers
88 views

Is it theoretically possible to project sound in a line, like flashlights?

I was wondering if there is a way to project sound waves on a particular point, like a laser? So that you can you can privately send a voice message to a specific person in crowd. The very first idea ...
1
vote
0answers
84 views

Can the intensity distribution behind edges and slits be explaint by the interaction with the surface electrons of the edges?

Reading about diffraction of EM radiation on edges, slits and multi slits as well as about electron diffraction around a wire I came to the conclusion that the intensity distributions on an observers ...
2
votes
1answer
54 views

Diffracted electron - where does it gain additional momentum?

When an electron is diffracted, the momentum after the diffraction has different direction than before. Where does the electron gain this momentum? This is related to this question, but it's ...
12
votes
3answers
183 views

Does the diffracted electron radiate photons?

When electron is diffracted after the slit it might follow different direction, than before the slit. That means, that going through the slit it gains some acceleration. And accelerated charge emits ...
2
votes
1answer
221 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 ...
2
votes
1answer
167 views

Is it possible to “focus” a radio wave to target an area much smaller than its wavelength?

Recently I was reading about a technology that uses radio waves to stimulate neurons to fire. The radio waves have the advantage of being able to pass through the skull (hence being non-invasive) but ...
1
vote
0answers
30 views

Rayleigh criterion for sound and parabolic microphone

Currently I am developing a parabolic microphone for a study project. I've heard and read that the maximum wavelength of sound that the given diameter microphone can focus is determined based on the ...
14
votes
2answers
615 views

Why are electromagnetic waves not able to pass through a hole with a diameter smaller than the wavelength? [duplicate]

I am doing research on Faraday cages for school, and I want to know how it works. Faraday cages can have holes in them, and if the diameter is smaller than the wavelength of waves you want to block, ...
4
votes
4answers
81 views

Possibility of making an experiment in a classroom to simulate DNA diffraction

I am a TA in a structural chemistry class. The professor want me to show students how Watson and Crick determined the structure of DNA from X-ray diffraction results of DNA crystals. The professor ...
1
vote
1answer
32 views

How does diffraction cause maxima and minima on a viewing screen

I have a problem in understanding the diffraction phenomenon. At first, it is described in simple way If a wave encounters a barrier that has an opening of dimensions similar to the wavelength, ...
2
votes
0answers
51 views

Diffraction grating from first principles

I have realised that a lot of books and online resources fail to give a detailed treatment of the derivation of the diffraction grating interference pattern. Normally only the result is stated. I was ...
0
votes
1answer
59 views

Can diffraction be used like gravitational lensing [closed]

I was thinking that in both the cases of diffraction and gravitational lensing, light is bend to some extent mimicking the lens effect. My Question is, Can diffraction be used like gravitational ...
2
votes
1answer
21 views

Zero Diffraction Plates: Why do they give such low diffraction signals?

In our laboratory we use silicon plates named "Zero Diffraction Plates". They are named so because they give extremely low diffraction signals in an XRD instrument (reflection mode). But how are these ...
0
votes
1answer
55 views

Fresnel lens/kinoform: How to model diffraction at the edges of zones?

I would like to find the intensity distribution of light due to the diffraction at the edges of zones on Fresnel lenses or kinoforms. (That is, location of orders, heights of maxima, etc.) I can't ...
1
vote
1answer
44 views

diffraction grating

Can I design a diffraction grating that has only two orders of diffraction, with the second one has a zero intensity? So the first order of diffraction would be bright and the weak light from far ...
0
votes
1answer
37 views

Intensity for Single-Slit Interference Pattern

In the derivation for the equation for the relative intensity of a single-slit interference pattern in my textbook, there is an assumption that I find a bit fishy. I know this equation works, so it ...
0
votes
0answers
33 views

Diffraction of a thin mirror

I have a question about a particular case of light diffraction. A laser light collides into a "hairline" mirror (I mean a straight line mirror that halves the wavelength dimension), see the image ...
2
votes
1answer
87 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 ...
0
votes
1answer
62 views

What is causing the separation of light in this image?

Reflection of keychain LED light on Macbook Pro (2014) screen I have also observed this phenomenon on my mobile phone and on a tablet. I assume this means it is somehow related to backlit ...
0
votes
0answers
31 views

Reason behind formation of doublets in diffraction spectrum

like if you see is Sodium (and also in Mercury), there are two discrete lines of Yellow color.. What's the reason behind formation of doublets?
1
vote
0answers
29 views

Property of $Cu$ so that it is used as target in in X-ray diffraction (XRD)?

Why only $Cu$ is used as target element in X-ray diffraction (XRD)? Why not other elements? And which rays has high intensity $k_\alpha$ or $k_\beta$?
1
vote
1answer
72 views

How does a non-diffracting beam form from a converging ring of illumination?

I am trying to intuitively understand the basics of the supplementary text of a recent publication from Eric Betzig's group on lattice light sheet microscopy (1). I am confused by the explanation of ...
0
votes
1answer
74 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) + ...
2
votes
0answers
17 views

Circular diffraction onto uneven surface

I'm trying to figure out how to solve for a surface using a circular diffraction. I have a pinhole diffraction that I'm projecting into a surface and I'm trying to figure out how to derive the shape ...
2
votes
4answers
94 views

Sound diffraction through a single slit

When sound waves diffract through a single slit, do they produce an interference pattern which is mathematically identical to that of light waves in the corresponding experiment?
0
votes
1answer
101 views

Diffraction to be explained without Huygens principle

Can we explain diffraction without using Huygens principle?
0
votes
0answers
91 views

Relation between size of obstacle, wavelength and diffraction

"If the boundary is merely an obstacle implanted within the medium, and if the dimensions of the obstacle are smaller than the wavelength of the wave, then there will be very noticeable diffraction of ...
1
vote
1answer
38 views

Does Bragg's law take into account atom size? (And should it?)

Bragg's law explains wave diffraction and interaction when electromagnetic waves hit a lattice structure: $$n \lambda = 2 d \sin \theta$$ See picture and details on Wikipedia. I am wondering if ...
2
votes
2answers
195 views

Diffraction by small holes

This is a follow-up to this question: What happens to waves when they hit smaller apertures than their wavelenghts? Hans Bethe wrote a paper in 1944, "Theory of Diffraction by Small Holes," Phys. ...
4
votes
5answers
366 views

What happens to waves when they hit smaller apertures than their wavelenghts?

I was wondering this for quite a long time now. Let's say you have a water wave (like ripples, not the ones you see during tsunamis) with wavelength 10 m. Imagine you put a boundary with an opening of ...
1
vote
0answers
84 views

Can the diffraction/interference pattern behind the slit (double slit) be calculated with Feynman path integrals (QED)?

I often see Feynman path integrals explained by a graphic which shows the slit and then the electron goes all possible ways behind the slit. Ok that is nice to understand the Feynman path integral, ...
1
vote
0answers
61 views

Intensity of Brightest Fringe of a multi-slit Diffraction

Let's say we have a multi-slit experiment with N slits.Since the central fringe has the most intensity, is there an equation to calculate the intensity of central fringe in terms of the intensity of ...
2
votes
4answers
6k views

What is the difference between diffraction and interference of light? [duplicate]

I know these two phenomena but I want to know a little deep explanation. What type of fringes are obtained in these phenomena?