Scalar diffraction theory
= Scalar diffraction theory
<Scalar diffraction theory> approximates <light> by one complex field satisfying a scalar <wave equation>. Aperture propagation is represented by an <integral> of secondary contributions, with vector <polarization of waves> and detailed electromagnetic edge conditions suppressed. The approximation is useful for many apertures large compared with <wavelength>, but is not an exact substitute for <Maxwell equations> at arbitrary apertures.