1. THEORY OF DIFFRACTION

2. Fraunhofer Diffraction
P(x,y,z) θ φ y X Y x O O`
z or D β α
direction cosines of observation point P

3. Rectangular Aperture Y b a X

4. Rectangular Aperture where Therefore field at P(x,y,z) is where
Thus intensity at P(x,y,z) is

5. Single Slit Diffraction
(Deduction from rectangular slit diffraction)

6. Single Slit Diffraction
(By integration from diffraction formula)
For single slit along y :

7. Single Slit Diffraction
(By integration from diffraction formula)
Therefore field at P (x,y,z) is
And intensity at P (x,y,z) is
along a line y=0

8. Double Slit Diffraction
(By integration from diffraction formula) x
Slit Spacing d
Slit Width a y

9. Double Slit Diffraction
(By integration from diffraction formula)
The double slit along x :
Field at point P(x,y,z) is
Now,
And

10. Double Slit Diffraction
(By integration from diffraction formula)