DIFFRACTION AND POLARIZATION

2. B.Sc.(MATHS)-‘4-SEM’
&NEHA JAIN MA’AM

3. Diffraction:- Fraunhofer’s Diffraction: Single slit; Double Slit.
Multiple Slits & Diffraction Grating. Fresnel’s Diffraction: Half-
Period Zones, Zone-Plate, Fresnel’s Diffraction at an Edge,
Fresnel Diffraction pattern of an Straight Edge.
Polarization:- Transverse-Nature of Light Waves, Plane
Polarized light; Production and Analysis, Circular and Elliptical
Polarization.
CONTENTS
DIFFRACTION OF LIGHT POLARIZATION OF LIGHT

4. of light :-
____ ___
.
Figs.- Diffraction Of Light.

5. Figs.- Diffraction of Light.
DIFFRACTION OF LIGHT

6. Real Life Examples Of
:-
l
***Diffraction Of Sunset Through Trees And Clouds :-
Figs.- Diffraction Of Light.

7. .
Fig.-

8. Fig. – Fresnel’s Slit Arrangement.

9. ________________________________________________________________________________________________________
__________________________
_____
Fig.-

11. ;
;
.

15. .
Fig.-

16. ,
, .

17. , .
, , ,
,

18. Fig.- Fig.-
ZONE - PLATE

20. .

21. .

22. Continued...

24. ,

25. :-

27. :-
________________________________

30. ,

33. :-
:
.
.
Fig.- Fresnel Diffraction at an Edge.
.
.
.
Fig.- Light
Diffraction by a
Razor Blade.

34. .
Fig.- Fresnel’s Diffraction Patteren Of A Straight
Fig.- Light Diffraction by
a Razor Blade.

35. Fig.

36. Fig.- Fraunhofer’s Slit Arrangement.

37. Fig.

39. .
.

40. -
;

41. -

42. ,

43. ,

44. Fraunhofer’s Diffraction At A Double Slit :-
Fig.- Fraunhofer’s Double Slit Arrangement.

46. Path Difference (∂)

51. Fig.-

52. Fig.-

53. Figs.- Diffraction Gratings.
:-
( )
Fig.-

55. Fig.- Diffraction Grating.

57. -
-

58. Fig.- Diffraction due to N – Slits.

59. POLARIZATION OF LIGHT:
-
Figs.- Polarization Of Light.
Fig.-
.
Fig.- Circular Polarization.
.
-
-
-
Polarization.
:-

60. When the polarised light coming through polariser is
incident on an analyser, parallel to the axis of polariser, then
emergent light has maximum intensity whereas when the
analizer is rotated at an angle then the intensity of emergent
light goes on decreasing and when it is perpendicular to the
axis of analyser then the intensity is minimum. This shows
that light waves are transeverse in nature......
Fig.- Light Wave.
Fig.- Unpolarized Light.
Fig.-
Fig.-

61. n2
-
Fig.- Polarization by Reflection.
Fig.- Plane-Polarized Light.
As per the Brewster’s Law, the maximum polarization takes place when the angle is 90 degrees in between the reflected ray
and refracted ray. This law was named after the famous Scottish Physicist, Sir David Brewster .

62. Malus' law states that the intensity of plane-polarized light that passes through an analyzer
varies as the square of the cosine of the angle between the plane of the polarizer and the
transmission axes of the analyzer.
;
PRODUCTION OF PLANE-
POLARIZED LIGHT:-
(POLARIZATION BY REFRACTION; MALUS LAW):-
Figs.- Action of Polarizer on Unpolarized Incident Beam.
Fig.- Polarizer and Analyzer.

63. ANALYSIS OF PLANE-
POLARIZED LIGHT:-
If a linearly polarized beam is incident on the polarizer (analyser), the irradiance of the transmitted beam
will vary with the rotation of the polarizer (analyser). And the irradiance of the transmitted beam varies as
the square of the cosine of the angle between the orientation of the incident linearly polarized light and
the transmission axis of the polarizer (analyser) i.e. intensity of transmitted light becomes twice maximum
and twice zero on one complete rotation. This is called the Malus Law, which plays an important role in the
modulation of light.
Analysing a Plane-Polarized Light:-
Fig.- Analysis of Plane-Polarized Light. Fig.- Polarizing Filters.
Fig.- Polarization Analyzer.

64. CIRCULAR POLARIZATION
TYPES OF POLARIZATION;
Fig.- Circular Polarization.
Fig.-
Figs.- Circular Polarization.

65. OF POLARIZATION:ELLIPTICAL POLARIZATION
TYPES
Fig.- Elliptical Polarized Wave.
Fig.-
Fig.- Elliptical Polarization.
Fig.- Elliptical
Polarization.

66. APPLICATIONS OF
POLARIZATION:-
Fig.- Blue Colour of the Sky due to Polarization. Fig.- Red Coloue of the Sun during Sunset due to Polarization.

67. Fig.- Polarized Light; From Blue Sky.
Fig.-
:-
We can use polarizing lenses to reduce glare. Light reflecting off horizontal surfaces like the road, water, or
snow is horizontally polarized. A polarizing filter oriented vertically will filter out the glare, but still allow
plenty of light through. A polarizing filter on your camera helps reduce shiny reflections.
MORE APPLICATIONS;