3. Introduction
Waves can be found in two forms.
• Mechanical waves propagate
through a medium, and the substance
of this medium is deformed. Eg: Sound,
water, ...
•Electromagnetic waves, do not
require a medium. Instead, they consist
of periodic oscillations in electrical and
magnetic fields generated by charged
particles, and can therefore travel
through a vacuum.
4. Reflection and Transmission
Why is it so important to learn about reflection?
It is because with every existing wave, there is
reflection and refraction.
Reflection is the change in direction of
a wave at an interface between two
different media so that the wave returns into
the medium from which it was originated.
8. Reflection and Transmission
A wave is partially reflected and
partially transmitted at the boundary
between media in which it has
different speeds.
1.Inverted Wave: when the wave
travels from a light medium (fast) to a
heavier medium (slow), the reflected
wave is inverted.
2.Un-inverted wave: the reflected
wave stays the same if the incident
wave travels from a heavier medium
to a lighter one.
9. Polarization
Definition
The polarization is described by
specifying the orientation of the
wave's electric field at a point in space
over one period of the oscillation.
10. Polarization
There are two types of linear polarization
• Parallel polarization:
The electric field vectors are
parallel to the plane of
incident.
• Perpendicular polarization:
The electric field vectors are
perpendicular to the plane
of incident.
11. Polarization
• Brewster’s Angle: also known as the
polarizing angle where given an
incident wave, there is no resulting
reflection.
12. The magnitude of the
reflection coefficient
depending on the
firing incident angle,
for the parallel and
perpendicular
polarization
13. Total Internal Reflection
There is an angle called critical angle at which
the incident wave is completely reflected.
From Snell’s Law :
16. Applications
• Undesired reflection:
– Sometimes reflection is unwanted so it is good to
know about it in order to develop techniques to
remove or minimize this reflection.
Example: we want to have
max transmission of the
incident light to go into the
binoculars. Solution is to cover
the lenses with a coating with
specific index of refraction to
minimize reflection.
