The setup we will use to demonstrate and study Fraunhofer diffraction is shown below. Note that it is
important to illuminate the objects with a planar wavefront to observe Fraunhofer diffraction. In many
cases, a reasonably accurate Fraunhofer pattern can be obtained with the raw laser beam (i.e., without the
beam expander) and with the screen sufficiently far away fromthe diffracting object (see Figure 1).