This applet allows the user to explore multiple slit diffraction by manipulating characteristics of the aperture and incident light to observe the resulting intensity.

The wavelengths of two monochromatic sources can be adjusted to illustrate the wavelength dependence of diffraction effects. The applet automatically calculates and displays the wavelength difference between the two sources.

The user controls the properties of the aperture including the number of slits, the slit separation and the slit width. When the slit width is set to zero, the slits are treated as point sources.

The intensity pattern of one or two monochromatic sources may be displayed . In addition, the combined intensity may also be displayed. The simulated diffraction pattern may be displayed either in color or in grayscale.