A question about the double-slit experiment

In summary: The radiation gets out of the slit because of the finite depth of the slit and the currents flowing in and out of the sides of the slit and across the face of the plate.
  • #1
r731
40
6
In the diagrams illustrating the double-slit experiment, I see waves extending longitudinally towards the the metal sheet. What if the waves were modeled differently so that they extended transversely in the diagrams? I've got the feeling that this can say something different.
 
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  • #2
r731 said:
What if the waves were modeled differently so that they extended transversely in the diagrams?

What do you mean by this?
 
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Likes etotheipi
  • #4
Vanadium 50 said:
What do you mean by this?

I mean that a beam is modeled as a wave crossing the metal sheet orthogonaly.
 
  • #5
r731 said:
I mean that a beam is modeled as a wave crossing the metal sheet orthogonaly.
Are you asking: if the incident radiation is polarised, does the angle between the polarisation direction and the slits affect the diffraction pattern? No it doesn't.
 
  • #6
r731 said:
I mean that a beam is modeled as a wave crossing the metal sheet orthogonaly.

You mean the beam is perpendicular to the sheet? This is the situation usually discussed in texts.
 
  • #7
I think that the [very confused] idea is that the picture shows the wave front extending at right angles to the direction of propagation.

In a transverse wave, the disturbance is at right angles to the propagation direction. For instance, the up-and-down motion of water when a wave moves past. Or the EM field direction for a radio wave.

In a longitudinal wave, the disturbance is in the propagation direction. For instance, the forward and back motion of the air molecules when a sound wave moves past.

But the drawings for the double slit experiment have nothing to do with this. They are drawing the wave front. The wave front is in the same place regardless of the nature of the disturbance that is being propagated. Waves always propagate at right angles to the wave front. It does not matter whether it is a transverse or longitudinal.
 
  • #8
Ibix said:
Are you asking: if the incident radiation is polarised, does the angle between the polarisation direction and the slits affect the diffraction pattern? No it doesn't.
One mechanism that can explain how the radiation gets out of the slit then you could treat it as an RF problem. Imagine a finite depth of slit and currents flowing in and out of the sides of the slit and across the face of the plate, near the slit. A simple analysis assumes that all the components that the diffraction integral uses are all parallel , in a particular direction. This is OK when not far from the axis but near the plane of the metal screen, it can't really be assumed and the depth of the slit sides become relevant - and also the material that the screen is made of.

The further off the axis, the lower the level of the flux, if you use a simple calculation but the more significant are the other, non-ideal, factors. These other factors will produce infinitessimal field contributions that are not actually parallel so you can't add them up simply.

It's just another example of end effects and edge effects that occur everywhere. It all depends on how accurate you want your answer.
 

Related to A question about the double-slit experiment

What is the double-slit experiment?

The double-slit experiment is a classic experiment in physics that demonstrates the wave-particle duality of light. It involves shining a beam of light through two parallel slits and observing the pattern of light that emerges on a screen behind the slits.

What is the significance of the double-slit experiment?

The double-slit experiment is significant because it provides evidence for the wave-particle duality of light, meaning that light can behave as both a wave and a particle. This has important implications for our understanding of the fundamental nature of light and matter.

What are the possible outcomes of the double-slit experiment?

The possible outcomes of the double-slit experiment depend on the conditions of the experiment. In general, there are two main outcomes: a interference pattern, where the light waves interfere with each other and create a pattern of light and dark bands, or a particle pattern, where the light behaves like individual particles and creates a series of dots on the screen.

How does the double-slit experiment relate to quantum mechanics?

The double-slit experiment is a key demonstration of the principles of quantum mechanics, which govern the behavior of particles at the atomic and subatomic level. It shows that particles can behave as both waves and particles, and that their behavior is influenced by observation and measurement.

What are some real-world applications of the double-slit experiment?

The double-slit experiment has implications for various fields, including optics, quantum computing, and particle physics. It has also been used to study the behavior of electrons and other subatomic particles, and has even been applied to studies of human perception and consciousness.

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