# Light through a slit

1. May 14, 2015

### Scheuerf

Why is it that when you shine a laser through a slit, it has the pattern that it does!

2. May 14, 2015

What kind of laser?

What kind of slit?

What kind of pattern?

When I shine a laser pointer through a 1cm slit it makes a single dot pattern on the wall, as expected.

I suspect you are asking about the double slit experiment, or some kind of spectral scattering through a grid of slits though.

3. May 14, 2015

### Scheuerf

A pattern like the one in the image I attached created when a laser shines through a small slit.

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4. May 14, 2015

### Staff: Mentor

The light waves passing through different parts of the slit interfere with each other, and the result is that pattern. Here's an overview:

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/sinslitd.html#c1

And here's a graphical method for calculating the intensity pattern:

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/sinint.html#c1

You can also use integral calculus to calculate it:

http://en.wikipedia.org/wiki/Fraunhofer_diffraction_(mathematics)#Solution_by_integration

5. May 14, 2015