Diffraction theory in terms of quantum mechanics and relativity

Diffraction properties of light can be derived from Quantum Mechanics and Relativity. Using the fact that position and momentum are conjugate variables, we show that the momentum distribution of light coincides with the well-known angular spectrum distribution The momentum distribution links quantum theory and relativity to classical diffraction theory. We also show that the Huygens Principle and the momentum distribution are conjugate expressions at the diffraction aperture. These considerations lead to the geometrical theory of diffraction.