2. Polarization
• ORDINARY LIGHT
Electromagnetic wave
Electric field E and magnetic field B are:
• Perpendicular to each other
• In phase
• Also perpendicular to the direction of
propagation
3.
4. • ORDINARY LIGHT
Unpolarized Light
• Contains large no.of atoms producing waves
with particular orientation of electric vector E
Resultant wave:unpolarized
wave:superposition of waves vibrating in
all possible directions
5. • POLARIZATION
Transforming unpolarized light into polarized
light.
Restriction of electric field vector E in a
particular plane so that vibration occurs in a
single plane.
9. Polarization by reflection
when the angle between the reflected and the
refracted beam is exactly 90 (see below), the
reflected wave is totally polarized, parallel to
the reflecting surface
10. • This is the condition for the
reflected wave to be 100%
polarized. The incident angle
satisfying this condition is
called the Brewster Angle.
13. Produce of plane polarized light by
passing through series of glass plate
14.
15. Polarization by absorption
• Light cab be polarized by using materials such
as tourmaline and polaroid.
• Polaroid-plastic sheet of polyvinyl alcohol
impregnated with iodine.
• Molecules of iodine polyvinyl alcohol are
oriented into long chains by stretching the
sheet.
16. • This material transmits about 80% of the light
polarized perpendicular to the chains of
molecules.
• Chains of molecules intearct with this
component and effectively absorb it.
17. Law of Malus
When a beam of completely plane polarized light is
incident on an analyzer, the resultant intensity of light (I)
transmitted from the analyzer varies directly as the
square of the cosine angle (θ) between plane of
transmission of analyzer and polarizer
i.e ,I ἀ cos2θ
I = I0cos2θ
• Where, I0 is the intensity of polarized light transmitted
through a polarizer
• I0 is half the intensity of unpolarized light
incident on the polarizer
