1. SCPY152 General Physics II June 19, 2015 Udom Robkob, Physics-MUSC
3 Wave Optics
SCPY152 General Physics II
June 19, 2015
Udom Robkob, Physics-MUSC

2. Topics Light waves Phasor Huygens’s principle Law of superposition
Double slit interference
Multiple slit interference
Thin films
Single slit diffraction
Single hole diffraction
Double slit diffraction
Grating diffraction

3. Light Waves
Light waves
Plane wave = sinusoidal field

4. Phasor
Rotating vector = phasor

5. Law of Superposition
Law of superposition

6. Law of Superposition
Phasor diagram

7. Double Slit Interference
Coherent light source = monochromatic light sources generate light waves in phase
Young double slit experiment

8. Double Slit Interference
Path different y

9. Double Slit Interference
Path different y
What is equation for destructive interference?

10. Multiple Slits Interference
In case of triple slit interference

11. Multiple Slits Interference
In case of triple slit interference
Three phasors are determined

12. Multiple Slits Interference
In case of triple slit interference
Three phasors are determined

13. Multiple Slits Interference
In case of triple slit interference
Three phasors are determined
Let try to analyze four slit interference pattern!

14. Interference from Thin Films
Let us determine thin transparence film of refractive index n and thickness d.
There are interferences at the front side and back side of the film.
We determine interference between light come from the front surface and the back surface of the film.

15. Thin Film Interferences
In case of front side interference
The interference depends on path different “2d” and phase different of the two light beams

16. Thin Film Interferences
In case of n>no, the first beam has phase shift from reflection at the front surface but not the second beam
Destructive
Interference:

17. Thin Film Interferences
Exercise

18. Thin Film Interferences
Exercise

19. Thin Film Interferences
In case of non-uniform film

20. Thin Film Interferences
In case of non-uniform film
In case of n>n0, for destructive interference

21. Thin Film Interferences
Newton’s rings R

22. Thin Film Interferences
Newton rings analysis

23. Diffraction Phenomena
We can see light diffraction in many places

24. Huygens’s Principle Huygens’s principle “Every point on the
wave front becomes
a new source of the
wave"

25. Single Slit Diffraction

26. Single Slit Diffraction
Phasor analysis

27. Single Slit Diffraction
Phasor analysis

28. Single Slit Diffraction
Phasor analysis-destructive interference
Path different

29. Single Slit Diffraction
Phasor analysis-destructive interference
Path different

30. Double Slits Diffraction
Double slit diffraction