Diffraction at multiple slits

Principle

This experiment should demonstrate to the students that light, when it is diffracted at n-fold slits, n - 1 secondary minima and n - 2 secondary maxima occur regularly between two adjacent primary maxima. Those are clearly visible, especially between the primary maximum of 0th order and the primary maximum of 1st order. Furthermore, the students should recognize that the intensity of the secondary peaks decreases with increasing number n of slits, and that in case of the transmission grating it is negligible. On the other hand, the intensity of the primary peaks increases with increasing n and is extremely high when using the transmission grating. In this way the experiment will facilitate the understanding of the way a transmission grating works.

Benefits

• Multifunctional light box - All-in-one: Can be used for geometric optics on the table, colour mixing and on an optical bench
• Extension with others sets at anytime, no additional light sources needed, recognition value for students

Tasks

How does the diffraction pattern change when the number of diffraction slits is increased? Examine the diffraction patterns created by 2, 3, 4 and 5 slits (multiple slits) of identical width and compare them with the diffraction pattern of a grating.