Difference between Fraunhofer and Fresnel diffraction

Difference between Fraunhofer Diffraction and Fresnel Diffraction→

S.No. Fresnel Diffraction Fraunhofer Diffraction
1. The distance between source to slit and slit to screen is finite. The distance between source to slit and slit to screen is infinite.
2. The shape of the incident wavefront on the slit is spherical or cylindrical. The shape of the incident wavefront on the slit is plane.
3. The shape of the incident wavefront on the screen is spherical or cylindrical. The shape of the incident wavefront on the screen is a plane.
4. There is a path difference created between the rays before entering the slit. This path difference depends on the distance between the source and slit. There is not any path difference between the rays before entering the slit.
5. Path difference between the rays forming the diffraction pattern depends on the distance of the slit from the source as well as the screen and the angle of diffraction. Hence the mathematical treatment is complicated. Path difference depends only on the angle of diffraction. Hence the mathematical treatment is comparatively easier.
6. Lenses are not required to observe or perform Fresnel diffraction in the laboratory. Lenses are required to observe or perform Fraunhofer diffraction in the laboratory.

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