 Kirchhoff's diffraction formula

Kirchhoff's diffraction formula is a foundational concept in the field of wave optics, specifically addressing the behavior of waves as they propagate from a source and encounter obstacles. Established by the physicist Gustav Kirchhoff in the 19th century, the formula provides a mathematical framework for predicting how light waves will diffract around edges and through apertures.

Approximation to Huygens-Fresnel principle.