Single slit diffraction

Diffraction takes place at any slit, obstacle, edge... Relative size of aperture to the wavelength defines the amount of diffraction in a slit.

The diffraction pattern consist of bright and dark fringes:

• Bright due to constructive interference: path difference between the waves is a multiple of wavelength (central fringe, exactly zero)


• Dark due to destructive interference: path difference between the waves is a multiple of half wavelength (first dark fringes around central fringe, exactly one half of a wavelength).

Check the relationship between the location of dark fringes, wavelength and aperture.