Fundamental of Optical Engineering Lecture 7
Boundary conditions:E and T must be continuous. Region 1:
Region 2: As we know that E is continuous.
Therefore,
For I ≥ I c implies “no refracted wave”. This allows light to propagate with no loss. This result does not depend on polarization and the wave. For I < I c I, there will be a reflected wave and the refracted The ratio of E r or E t to E i depends on the polarization (direction of E i ).
Plane of incidence is defined by the propagation vector of incident wave and normal to the plane of the interface.
Consider 2 cases: (i) Ei normal to plane of incidence. This is called ‘s-polarization’ or ‘perpendicular polarization’.
(ii) Ei in plane of incidence. This is called ‘p-polarization’ or ‘perpendicular polarization’.
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For normal incidence
We can also show from #3 that
The angle that makes no light reflection for p-polarization. Maximum polarization occurs at this angle for reflected light. Light reflected at any other angle but Brewster’s is partially linearly polarized.
Note: There is no Brewster’s angle for s- polarization.
Calculate Brewster’s angle for light traveling from a medium of refractive index 1.81 into a medium of index 1.52.
What is the angle of incidence for complete polarization to occur on reflection at the boundary between water (n=4/3) and glass (n=1.589) assuming the light comes from (a) water and (b) glass.
Unpolarized light Linearly polarized light Partially linearly polarized light Circular polarization Elliptical polarization
Birefringent median can transform polarization. Birefringent media have different refractive indices for orthogonal polarizations.
Let us consider
The output polarization is the same as incident one. This is called “Full-wave”.
This is called “Half-wave”.
This is called “quarter-wave”.
After leaving a crystal Consider real part of an electric field by assuming
Elliptrical polarization
These are components which transform polarization.