Disappearance of interference pattern in double slit

[elou]

TL;DR

I have discovered an article that expresses much better than I did in a previous thread that interference fringes disappear without being replaced by single slit interference

https://www.nature.com/articles/s41598-019-43323-2. Please note Figure 4 p.4 of the article, and the following description:
"
In Fig. 4(h), the right slit is completely blocked, the interference fringes have disappeared completely and only the diffraction image of the open left slit remains." (p.4).
As in a previous thread, the question why a single slit interference pattern does not appear, remains unanswered.

 

[Dale]

As in a previous thread, the question why a single slit interference pattern does not appear, remains unanswered.

From the article figure 4g is a single slit interference pattern which is often called a diffraction pattern.

 

[weirdoguy]

As in a previous thread, the question why a single slit interference pattern does not appear, remains unanswered.

No no, it remains answered, you just don't like the answers.

 

[elou]

No no, it remains answered, you just don't like the answers.

Please remind me of it. I promise I will do my best. Just to make sure we are talking about the same thing: do you see an interference pattern in 4h?

 

[elou]

From the article figure 4g is a single slit interference pattern which is often called a diffraction pattern.

If I understand you correctly. as well as @weirdoguy , it is a matter of terminology? When I say "interference pattern" you all understand "diffraction pattern"?

 

[elou]

Don't single slit interference patterns look very much like double slit interference patterns?

 

[Dale]

If I understand you correctly. as well as @weirdoguy , it is a matter of terminology? When I say "interference pattern" you all understand "diffraction pattern"?

When you say “single slit interference pattern” it is the same as “diffraction pattern”

 

[elou]

When you say “single slit interference pattern” it is the same as “diffraction pattern”

Okay, that could explain the confusion. Then, I should have said, the single slit interference pattern that looks almost like the double slit interference pattern.

 

[Dale]

, the single slit interference pattern that looks almost like the double slit interference pattern.

I have no idea what you mean here. Does figure 4g look almost like figure 4a?

 

[Nugatory]

Then, I should have said, the single slit interference pattern that looks almost like the double slit interference pattern.

What the patterns look like depends on the details of the shape, size and position of the slits. To determine what they should look like or what we expect them to look like, we have to do the necessary calculations.

As in a previous thread…

Please do take a moment to review the forum rule about restarting closed threads.

 

[Nugatory]

In this thread we are just repeating what was said in the previous thread, to no greater effect.

The thread is closed. @elou, the best way for you to continue your interest in wave phenomena would be to get hold of Crawford’s “Waves” (mentioned in the previous thread) or equivalent and work through it.

 

[Ibix]

Don't single slit interference patterns look very much like double slit interference patterns?

They can do. But the scale of a pattern depends on the sizes and separations of the slits. The gap between the slits in 4b in the diagram Dale posted is 8 times the width of the slits, so the double slit pattern is about 8 times narrower than the single slit one. The single slit central maximum is double width, though, so you'd expect about 16 maxima of the double slit pattern in the central maximum of the single slit pattern.

So in 4a you are seeing a single maximum of the single slit pattern multiplied by about sixteen maxima of the double slit. In 4g you are just seeing the central maximum of the single slit pattern.

Thanks to @Nugatory for re-opening the thread so I could post the quantitative point.

 

[PeterDonis]

When you say “single slit interference pattern” it is the same as “diffraction pattern”

And just to re-emphasize, @elou, this was already stated in your previous thread.