There are many other examples of diffraction. The picture below shows diffraction from a single slit where waves from different parts of the slit interfere with each other. To get the field at some point on the detection screen, one should integrate over the slit.

* Example:
Derive the location of the nodes in the diffraction pattern from one slit of width .
Now try to compute the intensity distribution for single slit diffraction.*

Jim Branson 2013-04-22