Kirchhoff's Diffraction Formula

Kirchhoff's diffraction formula approximates the intensity and phase of light in optical diffraction, describing light fields in the boundary regions of shadows. It can be used to model light propagation across a wide range of configurations, either analytically or through numerical modeling, giving an expression for the wave disturbance produced when a monochromatic spherical wave is the incoming wave of the situation under consideration, and it is derived by applying the Kirchhoff integral theorem, which itself uses Green's second identity to solve the homogeneous scalar wave equation for a spherical wave under certain approximations. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/