RECONSTRUCTION OF OPTICAL FIELDS IN THE PROCESS OF NEAR-FIELD DIFFRACTION TO FRAUNHOFER DIFFRACTION

Fraunhofer diffraction is one of the important physical concepts in optics, where the diffraction patterns of single slits, square apertures, and circular apertures in Fresnel diffraction are well known. In this paper, we discuss the phenomenon of light field reconstruction of optical fields in the process of near-field diffraction transiting to Fraunhofer diffraction (far-field diffraction). It is found that the intensity structure will change and the optical energy will redistribute in the reconstruction of one-dimensional and two-dimensional optical fields. Especially, the a autofocusing effect of the light field is found when a plane wave passes through a two-dimensional aperture (square hole and circular hole). Taking elliptical light fields and astigmatic elliptical light fields as examples, we discuss the deformation and rotation of light spots in the reconstruction process of two-dimensional light fields. Experimentally, Fraunhofer diffraction can be achieved by a convex lens.