Far-field Diffraction Patterns of Two Slits

The diffraction of a scalar wave by two parallel slits in a plane screen is examined by a new method which uses an orthogonal set of functions and Fourier transformations. The far field is obtained for the case of normal incidence and numerical results are given for k = 0·2 ? 5 and D =3 ? 10, where k is the wavenumber and D is the slit separation.