Bending of light near the edges of an obstacle or slit and spreading into the region of geometrical shadow is known as diffraction of light.
The diffraction phenomenon is classified into two types :
1. Fraunhofer diffraction : The source of light and the screen on which the diffraction pattern is obtained are effectively at infinite distance from the diffracting system. In this case, we consider plane wavefront. The diffraction pattern is obtained by using a convex lens.
2. Fresnel diffraction : The source of light and the screen are kept at finite distance from the diffracting system. In this case, we consider a cylindrical or spherical wavefront.
The two types of diffraction are Fresnel diffraction and Fraunhofer diffraction. Fresnel diffraction.
