Examples of fresnel diffraction on an aperture (diaphragm, pinhole). A round aperture is placed in the path of a Gaussian beam emitted by a laser. The resulting diffraction pattern is observed on a screen some distance away. The image on the far right shows a central bright spot in the fresnel diffraction of a shadowgram. Composite color enhancement of 9b1144, 9b1142, 9b1150.