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1answer
965 views

Diffraction-Long versus short waves

Why is it that long waves diffract more than short waves? I know that refraction has a quantum mechanical explanation, does diffraction have a similarly complex explanation? My teacher in high school ...
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0answers
45 views

Bass and Treble-Car Steroes

In a car which phenomenon, diffraction or the resonant frequency of the car, lends itself more to the ability of bass to go farther? Related Answer: Why do bass tones travel through walls?
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3answers
232 views

Is it possible to surpass the diffraction limit for telescopes?

Telescopes have angular diffraction limit depending on the observed wavelength and aperture diameter. I've read that it's possible to go beyond the limit for microscopes. But is it possible to do the ...
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1answer
113 views

Hearing sound around corners

I've been taught that diffraction is the reason why we can hear around corners, since the wavelength of sound is approximately 10 cm (smaller than a door or a window). I wonder how can this be ...
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1answer
292 views

Young's Double slit experiment (Finding the value for slit separation) [closed]

The question illustrates mono-chromatic red light passing through 2 slits and forming an interference pattern on the screen. The question then asks to suggest a suitable value for the slit separation. ...
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2answers
595 views

What's the physical significance of using fourier transform for diffraction?

I am studying some basic idea of diffraction and there mention in far field, the diffraction pattern could be understood by Fourier transform. But I just don't understand what's the physical fact for ...
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2answers
638 views

Optimal telescope size?

Consider a diffraction-limited telescope with unobstructed aperture $D$. Such a scope is capable of yielding an angular resolution $\alpha$ that scales as $\lambda/D$, with $\lambda$ denoting the ...
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1answer
296 views

Young's double slit experiment viva question

My professor asked me (in my viva exam), "If, in the Fraunhofer single slit diffraction experiment, if we have 2 slits instead of one (at very short distances), What would happen?" I answered with ...
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4answers
6k views

How can a single slit diffraction produce an interference pattern?

How can a light passed though a single slit produce a similar interference pattern to the double-slit experiment? How does the diffracted wave produce the points of cancellation and reinforcement, if ...
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1answer
261 views

Planes of graphite crystal on diffraction experiments

When doing electron diffraction on graphite (a popular experiment for students at universities) always diffraction at these two planes with distances $d_1$ and $d_2$ are observed: But a plane ...
6
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1answer
158 views

Will a football (soccer) diffract?

Apparently all objects have wavelike properties, so, if we kick a football (soccer ball, if you must) through a pair of posts, does the ball in any sense diffract? If this is ridiculous then let me ...
5
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2answers
139 views

Smaller Airy disk with another lens?

Is it possible to reduce the airy disk size produced by one lens with another lens placed after the previous one? For example, parallel ray incident on first lens L1 (without aberration), then there ...
3
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2answers
299 views

X-ray diffraction from Metals

Is X-ray crystallography is possible for metals? Or not due to absorption?
2
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1answer
588 views

Covariant derivative

I would very much appreciate some help in The following: What is 2nd order covariant derivative $$\nabla_i\nabla_jf(r)$$ in terms of $r,\theta, g(r)$ and partial derivative, given that the metric ...
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1answer
125 views

Factors that make beam divergence worse after refocusing

A beam of light of width $W$ and wavelength $\lambda$ with divergence that is diffraction-limited is refocused with an optical element placed at a distance $D$ from the beam source. Will the refocused ...
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1answer
280 views

How fat is Feynman’s photon?

According to my calculations, it is a lot skinnier than Airy’s photon, but still a whole lot fatter than a straight line. So, how does a photon get from point A to Point B? The ray optics ...
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3answers
259 views

Beam waist at extremely long distances

A beam of light of wavelength $\lambda$ and width $W$ needs to be focused at a distance $D$ to a spot not bigger than $w_S$, which stands for 'width of sail'. Now, the diffraction limit says it ...
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3answers
132 views

How do I determine where I can no longer hear sound?

A teacher stands well back from an outside doorway that is 95 cm wide and blows a frequency of 600 Hz. The door faces north. Assume the speed of sound is 340 m/s and that there are no reflections. At ...
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1answer
173 views

Is diffraction affected by interaction between photons and electrons?

Suppose we take a sheet of ordinary metal, make a narrow slit in it, and shine a light beam through the slit onto a screen. The light beam will diffract from the edges of the slit and spread out onto ...
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0answers
77 views

about wavefunction and vector entries

I am beginer of physics and I am studying some very fundamental idea of quantum mechanics by myself. In the introducing book I am reading, there is an example to show a particle diffraced by a slit or ...
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1answer
571 views

Diffraction through a single slit?

I'm having some trouble finding the answer to this homework question: A wide beam of light from a laser with a wavelength of 450.0 nm is incident on a long narrow opening that is 0.300 mm wide. ...
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1answer
101 views

Diffraction through the slit

In book "Quantum Mechanics and Path Integral", 3-2 Diffraction through the slit: Under the fig. 3-3, why did Feynman say that we cannot approach the problem by a single application of the ...
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1answer
1k views

Application of diffraction problem!

Here is a problem that I am working on, which is the applying the concepts of diffraction to the setting of the sun: Air has a small, usually negligible index of refraction. It is 1.0002926. This ...
3
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1answer
152 views

How small can diffraction grating be?

Like in title, how small can diffraction grating be? And, of course be "fully operational". I mean, littles diffraction grating possible that still works as full-sized one.
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1answer
612 views

Calculating diffraction patterns using FFT

I'm trying to write a piece of code that calculates a diffraction pattern similar to an X-ray experiment using a FFT. From my knowledge, the diffraction pattern for point particles can be calculated ...
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2answers
153 views

X-ray diffraction from crystals and time-averaging

To calculate the elastically scattered intensity of x-rays from crystals, one classically considers scattering from a free electron first and then one sums up the scattered em-fields of all electrons ...
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1answer
126 views

Does diffraction contribute to the Black Drop effect?

Two reasons are given to explain the black drop effect here, but I think I came up with a third. Consider a two-dimensional cross section of the situation just after second contact and just before ...
5
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1answer
593 views

How can the Huygens-Fresnel principle be derived from the Maxwell equations?

The Huygens-Fresnel principle states that every point to which a luminous disturbance reaches becomes a source of a spherical wave. I have been trying to understand this considering a infinite screen ...
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1answer
223 views

Rayleigh diffraction by circular aperture

I am a beginner to physics and would need an explanation on a statement in a book "Karttunen, Fundamental astronomy". In a section named "Rayleigh diffraction by circular aperture", author states: ...
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2answers
348 views

Effect of a wavefront deformation on the far-field diffraction pattern of a TEM00

By performing Matlab simulations on a TEM00 mode (approximated by a gaussian intensity profile with a flat wavefront), I got the impression that applying wavefront deformations (such as a single ...
3
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1answer
77 views

Describing quantum intereference with only currents and densities

I know about and believe to understand the general wave equation based Kirchhoff diffraction formula, which in the Fraunhofer limit leads to a farfield complex wave function by Fourier transforming ...
2
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1answer
353 views

What's the mathematical background to the representation for Gaussian beams?

Background A general optical system (not necessarily having an axis of rotational symmetry) can be represented, for small deviations from a base ray, by the matrix transfer equation, $$ ...
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1answer
112 views

Describing the surface of a sphere in Huygens' Principle

$U(P) = \frac {iU(r_0)}{\lambda} \int_{S} \frac {e^{iks}}{s} K(\chi)\,dS$ Where $S$ describes the surface of the sphere, how is the surface of the sphere described? Sorry if you feel this is quite a ...
4
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2answers
174 views

What are the lines visible between two cards held edge-to-edge?

Hold two cards (say credit cards) edge to edge, anything from a very slight touch to about 1/3 mm separation, in front of any ordinary light source. When I do this I see several fine dark parallel ...
3
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1answer
486 views

Calculating Fraunhofer diffraction patterns

How does one calculate the Fraunhofer diffraction pattern for the following arrangement of slits: |...|...........|...| ..a.....3a......a (Four slits arranged linearly, spaced a distance a, 3a and ...
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1answer
1k views

reflection, refraction and diffraction occur in radio waves, which one occurs the most?

One of the things about Radio waves is that they undergo different behaviors such as reflection, refraction and diffraction when in contact with obstacles such as walls, buildings etc. what i want to ...
3
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1answer
368 views

Why is the diffraction pattern for an annular aperture the difference of the two Bessel functions?

Inspired by this question, the pattern for the annular intensity is given by the square of the difference of the two Bessel functions. I would have thought the sum was more appropriate, could someone ...
3
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2answers
181 views

The Bahtinov focusing mask

I'm looking for a webpage or a book or reference that might give me a better (and hopefully more scientific) understanding of how the Bahtinov mask works (which I understand to be the same as ...