Calculation of the Diffraction Field of a Circular Aperture Irradiated by a Point Source

Circular aperture diffraction is important to the beam transmission and transformation,the diffraction imaging of optical imaging system and optical information processing.After the integral expression for the circular aperture diffraction irradiated by a point source is gotten from the Kirchhoff diffraction integral formula,a numerical calculation method is proposed,and the calculation formula for the light field of circular aperture Fresnel diffraction and its special circumstance circular aperture Fraunhofer diffraction irradiated by a point source is deduced.Then the diffraction patterns of paraxial zone are simulated with the Matlab software,and the simulations show that these two calculation methods are both effective and reliable and are conducive to the development of diffraction theory and technology.