Diffraction through a single slit

In summary: The figure shows intensity as a function of angle (0 degrees is the center) for three experiments that use single slits of different width. The one on the right has the slit width far larger than the light's wavelength so the peak width is very small, the one in the middle has the slit width far less than the light's wavelength so the peak width is very large, and the one on the left has the slit width a bit larger than the light's wavelength, so the peak width is... sort of normalish. When I say that the slit width is far larger than the light's wavelength, I mean by a factor of 100. When I say that the slit width is far less than the light's wavelength, I also
  • #1
Cade
92
0
This isn't a homework question per se, I'm just wondering about something in my textbook (Halliday & Resnick) that isn't clear to me:

This figure shows intensity as a function of angle (0 degrees is the center) for three experiments that use single slits of different width.
rBKKC.png


The one on the right has the slit width far larger than the light's wavelength so the peak width is very small, the one in the middle has the slit width far less than the light's wavelength so the peak width is very large, and the one on the left has the slit width a bit larger than the light's wavelength, so the peak width is... sort of normalish.

When I say that the slit width is far larger than the light's wavelength, I mean by a factor of 100. When I say that the slit width is far less than the light's wavelength, I also mean by a factor of 100.

1) I'm curious about the right-most image. If the slit is very wide and the light coming in was a wave parallel to the slit, it would hardly diffract light through its center, allowing most of the wave to pass through in the same direction. But if the intensity on screen is very narrow when it isn't diffracted, does this mean that the light in this example is from a thin beam (perhaps a laser)?

2) Would I be correct in saying that if the light in this example were a wave passing through a very wide slit, the intensity would be high and even, with diffraction starting at the edges where it diffracted off the sides of the slit?

3) If the slit is very narrow, the wave or beam would come out in a hemispherical shape (Huygens-Fresnel principle). This would give it a wide center diffraction maximum. For this case, because the slit is extremely narrow, I think it doesn't matter how "wide" the light coming in is. Is this correct?
 
Last edited:
Physics news on Phys.org
  • #3
Thanks, that's an interesting simulation.

Does image width mean width of the light coming in? I.e. very large image width for a plane wave and very thin image width for a laser beam?
 

What is diffraction through a single slit?

Diffraction is the bending or spreading of waves as they pass through an opening or around an obstacle. In the case of a single slit, light waves are diffracted as they pass through the narrow opening, creating a pattern of bright and dark fringes.

What factors affect the diffraction pattern through a single slit?

The diffraction pattern is affected by the width of the slit, the wavelength of the incident light, and the distance between the slit and the observation screen. The pattern becomes more spread out as the width of the slit decreases and as the wavelength of light increases. The pattern also becomes narrower as the distance between the slit and the observation screen increases.

How is the intensity of the diffraction pattern distributed?

The intensity of the diffraction pattern is distributed in a bell-shaped curve, with a central maximum and decreasing intensity on either side. The width of the central maximum is determined by the width of the slit, while the overall intensity of the pattern is affected by the wavelength and distance between the slit and observation screen.

How does diffraction through a single slit differ from double-slit interference?

In diffraction through a single slit, the light passing through the opening spreads out and creates a pattern of bright and dark fringes. In double-slit interference, the light from two separate sources creates a pattern of bright and dark fringes due to the interference of the waves.

What practical applications does diffraction through a single slit have?

Diffraction through a single slit is commonly used in experiments to study the properties of light waves. It also has practical applications in devices such as diffraction gratings, which use a series of slits to produce a spectrum of colors, and in optical instruments such as microscopes and telescopes to improve image resolution.

Similar threads

  • Introductory Physics Homework Help
Replies
11
Views
943
Replies
11
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
34
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
1K
Replies
2
Views
209
  • Introductory Physics Homework Help
Replies
10
Views
8K
Back
Top