Laser Diffraction - Multiple Slits
To show the transition from one slit to multiple slits and the diffraction grating.
Laser cart with multiple slit slide.
A slide contains an array of 1, 2, 3, 4, and 5 slits. The single and double slit patterns are familiar. For N slits, where N is 3 or more, N-2 maxima of lesser intensity appear between the primary maxima. As N increases, the primary maxima increase in intensity as the 1st, 2nd, 3rd, 4th,etc. order spots, and these lesser maxima decrease in intensity until they cease to exist for a grating.
Kenneth S. Mendelson and Frank G. Karioris, Multislit diffraction patterns using a slit-grating combination, AJP 63, 53-56 (1995).