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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32 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 ...
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32 views

Given a light diffracting through an aperture of radius r, how would we find the radius of the beam at a position x meters away?

If we have a light source, say a laser or LED, diffracting through a circular aperture of radius $r$, how would we find the radius of the beam at a position $x$ meters from the optical axis? I ...
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36 views

Wave equation for spatially incoherent light beam

I would like to know what happens to a plane wave from a laser $$\Psi(r)=e^{ikr}$$ after it passes a ground glass. Would I just get a superposition of spherical waves? $$\Psi(r) = ...
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42 views

How does the interaction between individual electrons of beams affects the diffraction pattern?

Consider the diffraction of an electron beam. How does the interaction between individual electrons of beams affects the diffraction pattern? If it really affects the diffraction pattern, then is ...
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58 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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37 views

Is there sound diffraction grating? [closed]

Sound is also a wave phenomenon. Therefore, is there any counterpart of the usual optical grating for sound?
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57 views

Huygens principle and wave propagation

I have seen the following illustration online and had a brief lecture about Huygens principle. As far as I understood, it suggests that every point in a wavelet acts like a point source to wavelets, ...
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50 views

Differences between single-slit/obstacle diffraction

In class, we have derived the formula for a single slit diffraction (slit length $a$) and it seems that the same equations are used when talking about diffraction around an obstacle of width $a$ (like ...
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44 views

Two-slit experiment, why $\exp(ix)$ and $\exp(-ix)$?

I am looking at an example problem from optics with two narrow slits with light shining through both. The light through one slit is 5 times the amplitude of the light through the other. I know from ...
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69 views

How is the uncertainty principle protected for a single electron diffraction?

In the experiment where electrons are sent one by one through a slit on a screen behind which there is an electron detector, the electron is said to have a definite position at the time it crosses the ...
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1answer
43 views

How do atoms scatter X-rays?

I am learning the theory behind X-ray diffraction but I have a question. According to the textbook I am using, X-ray tubes (in diffractometers) produce near monochromatic X-rays. In other words, they ...
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23 views

Diffraction of rays [duplicate]

To all the physics experts here this might sound like a stupid question, but I give it a try: This is a sketch of how you usually learn about the effect of diffraction in an experiment: Now I was ...
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411 views

How can beam divergence be corrected for in a CO2 laser cutter?

I have a 90W RECI CO2 laser tube that I recently measured the beam divergence on. This was done by pointing the laser at a fire brick and melting it for a few seconds at different distances. Multiple ...
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50 views

Optics Diffraction Grating Plot

I was unsure whether to post this in physics stackexchange or mathematica stackexchange, so I posted it in both. I'm trying make an intensity plot for a diffraction grating that contains 100 ...
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23 views

Diffraction through 1 slit - light levels at minima points are zero or somewhat higher?

During a few diffraction experiments, my partner and I realized that during a 2 slit experiment all minima points surely cannot be completely dark, due to the fact that the two light sources (1 from ...
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15 views

Diffraction grating with film covering half of slits

If I have a film covering part of my slit of finite width is it justified to take the integral of the wave elements with there phase difference as a function of x across each half separately ...
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1answer
54 views

Can a magnetic ball “diffract” around a metal object?

Consider a magnetic ball falling through a copper pipe. It falls slower than it would if it wasn't near any copper. We can use this to determine that the closer a magnetic ball is to copper, the ...
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144 views

Is Wikipedia wrong about Huygens-Fresnel Principle?

Someone posted a question about why backward waves don't exist according to the Huygens-Fresnel principle: Why doesn't a backward wave exist? In following up on this question I read the Wikipedia ...
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193 views

Does diffraction take place in Young's double slit experiment?

In diffraction experiments interference takes place along with diffraction? Does diffraction take place in Young's double slit experiment? If it does take place then why don't we get the pattern of ...
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278 views

Difference between Youngs double slit experiment and Double slit diffraction?

Both these experiments have double slits but in one interference takes place and in the other both interference and diffraction. If diffraction takes place in double slit diffraction then it should ...
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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 ...
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1answer
74 views

In a double slit experiment, fringe separation is constant. However in a diffraction grating fringe separation is not constant. Why is this?

Can you explain this as simply as you can? I am currently in high school and I've been wondering why? Correct me if my question is wrong, and if my assumption in my question is wrong, would you help ...
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1answer
49 views

de Broglie's Hypothesis [duplicate]

I've recently understood de Broglie's hypothesis, and I understand that a necessity for electrons to show diffraction is that the size of the aperture they pass through must be of the order of their ...
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1answer
69 views

Diffraction pattern in one continuous slit

Will a noticeable diffraction pattern appear if I use a single continuous slit, say a ring shaped one?If yes, can it be explained how the slits were paired for interference observations , and is there ...
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2answers
70 views

Confusion in difraction experiments

I had a confusion in the diffraction experiment about which I was taught in school. According to the formula we Derived The width of the central maxima decreases on decreasing width of slit and vice ...
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53 views

Fraunhofer diffraction at circular aperture - integration of bessel function

I'm trying to understand the calculation here: http://en.wikipedia.org/wiki/Fraunhofer_diffraction_(mathematics)#Circular_aperture for the solution by integration, but I plain and simple fail to see ...
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66 views

Energy of neutrons in crystal diffraction

The spacing of the atoms of a crystal is 159 pm. A monoenergetic beam of neutrons directed normally at the surface of the crystal undergoes first order diffraction at an angle of 58° from the ...
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65 views

Why is there no exact formula for position of maxima in single slit interference

On this website (http://www.ualberta.ca/~pogosyan/teaching/PHYS_130/FALL_2010/lectures/lect35/lecture35.html) it says that the formula $\sin(\theta_{max}) = (m+\frac{1}{2})\lambda$ derived for the ...
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59 views

Formula for intensity and central bright fringe in Fraunhoffer diffraction from single slit

I want to understand why, theoretically, the central bright fringe has maximum brightness/intensity. And where does the formula $I=I_0\left(\frac{\sin B/2}{B/2}\right)^2$ come from? My book says it is ...
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157 views

In the double slit experiment with electrons why the single slit case is not diffracting as photons would have?

The famous double slit experiment used in books to describe the duality of particles nature usually presents a case where only one slit is open and there is no diffraction. Aren't we supposed to see ...
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102 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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55 views

does the Fresnel approximation apply in the far field?

Most sources I've looked at treat far field diffraction and near field diffraction as separate cases, with the former using the Fraunhofer approximation and the latter the Fresnel approximation. In ...
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45 views

Is Rayleigh/Wood's anomaly simply the grazing order diffraction?

Is Rayleigh/Wood's anomaly simply the grazing order diffraction? I read some related papers but I am still confused, can I simply understand it as a surface wave propagating on the surface because of ...
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62 views

what is the effect on the fringe separation of a single slit diffraction when the wavelength is larger than the slit width? [closed]

i know that the diffraction pattern observed is stronger when the slit width is equal to the wavelength of the wave passing through, but what will happen if the slit still got narrower and became ...
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34 views

What are the exact setups to observe a wave function and its collapsed state?

I was reading this article: http://io9.com/5528321/how-smart-do-you-need-to-be-to-collapse-a-wave-function and I need some clarification on the experiment setup. My current understanding is that if ...
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2answers
47 views

Diffraction of light

If $l_1$ and $l_2$ are parallel how can they both can hit same spot? Why their difference in path length is $l_2 - l_1 = d \sin \theta$ instead of 0?
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58 views

Source of a parabolic wavefront

The Huygens-Fresnel diffraction integral has been formulated for incident spherical waves. A source of a spherical wave is kind of intuitive, since the perpendicular rays of the sphere converge into a ...
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3answers
51 views

In diffraction process, how to describe the edge in the sense of particle-wave duality?

In diffraction experiments photons show behind an edge intensity distributions in the form of fringes. It seems to be without doubt that the edge is a part of the game. My question is, how to describe ...
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97 views

Why light rays gets scattered when it enters a translucent window pane?

Consider the light source is the light post, outside the window of my house (Pic 1). When the rays from the light post enters through the window pane which is translucent gets scattered and forms a ...
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85 views

Fresnel diffraction approximation (parabolic waves)

The Huygens-Fresnel principle (Introduction to Fourier Optics, Goodman), $$ U(x,y)=\frac{z}{i\lambda}\int_\Sigma U(\xi,\eta)\frac{e^{ikr}}{r}d\xi d\eta\,, $$ where $\cos \theta=\frac{z}{r}$, shows ...
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45 views

A problem in deducing $|\psi(x)|^2 \propto \cos^2(\pi sx/\lambda z_o)$ in diffraction by two slits experiment

In Quantum Mechanics for scientists and engineers by David Miller, he explains the diffraction by two slits (page $13$) and considers a beam of electrons whose wave function is $\psi(x)= \exp(ikr)$ ...
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29 views

Determining angle of distortion in a Rhombohedral unit cell

I have a film which is rhombohedrally distorted. I would like to measure by Xray diffraction, the angle of distortion of the unit cell. I can measure the in-plane and out-of-plane lattice parameters ...
3
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2answers
200 views

The equation of diffraction

I have learned the equation of diffraction, which is: $$\sin \theta=\frac{\lambda}{d},$$ where $\lambda$ is the wavelength and $d$ is the gap width. So, when the gap width is closer to the ...
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1answer
57 views

Diffraction of light around an object & human perception

A wave exhibits diffraction when it encounters an obstacle that bends the wave or when it spreads after emerging from an opening. Diffraction effects are more pronounced when the size of the ...
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1answer
66 views

How to transmit light ideally through not parallel tiny holes within a metal case?

I currently try to transmit light through a tiny hole of one side of a metal case in order to receive the light on the other side of the case. The tiny holes are not parallel (see image 2). Using ...
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2answers
68 views

Refraction, diffraction or reflection of human voice

Why is possible to hear in an open space someone's voice even if he's not facing me? Is it because of refraction, diffraction or reflection of the sound wave?
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2answers
87 views

How is the virtual image reconstructed from a hologram?

To make a hologram a film is exposed to an incident plane wave and wave from the object to record the interference pattern on the film. The principle is commonly explained in a way like that in p.1212 ...
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52 views

Why array of telescope is used?

To increase the resolution of an instrument, smaller wavelength and larger aperture is desirable. It is mentioned in some textbooks that the "effective" diameter of a telescope can be increased by ...
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122 views

x-ray diffraction of crystals

In explaining x-ray diffraction of crystals, usually the approach is to consider the atoms absorb radiation and scatter it, at some angles constructive interference occur and bright spots can be ...
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114 views

Question about dark fringe in diffraction

In finding the angle for the mth dark fringe of single slit diffraction using Huygen's principle, they usually split the slit into equal portions. For example, to find the first dark fringe the slit ...