Differences Between Fraunhofer and Fresnel Diffraction

S.No.	FRAUNHOFER DIFFRACTION	FRESNEL DIFFRACTION
1	Source and screen are placed at infinite distances from slit	Source and screen are placed at finite distances from slit
2	Wave front falling on the aperture is planar	Incident wave front is either spherical or cylindrical
3	The diffracted wave front is planar	The diffracted wave front is either spherical or cylindrical
4	Usually biconvex lenses are required to study diffraction at laboratory	No lenses are required
5	The maxima and minima are well defined	The maxima and minima are not well defined

Arago,Poisson and Fresnel - The Trio of Diffraction

              François Arago                      Siméon Denis Poisson                    Augustin-Jean Fresnel

Poisson-Arago Spot

POISSON-ARAGO CRATER - NOT ON THE MOON !

Fresnel Half Period Zones

Newton's Rings - Shot @ Our Laboratory

NEWTON RINGS

NEWTON'S MOUNT - A 3D SURFACE PLOT OF NEWTON RINGS - PROCESSES WITH IMAGEJ

NEWTON'S MOUNT - ANOTHER PERSPECTIVE - CROSS WIRES  MAKE A DEEP CUT IN THE MOUNT

👆Note : There's a Dark Spot at the Center. Reason: Stokes' Rule 👉 A path change of λ/2 or phase change of π occurs in the light wave, when light gets reflected from denser to rarer medium No phase change takes place if it is reflected from rarer to denser medium.