
POLARIZED LIGHT 163
If we wish, we can dene a
ˆ
y polarizer as
P
y
=
00
01
, (6.99)
which we will nd convenient although not necessary. More realistically, we can describe an
ˆ
x polarizer by
P
x
=
τ
pass
0
0 τ
block
, (6.100)
where τ
pass
(slightly less than unity) accounts for the insertion loss, and τ
block
(slightly larger
than zero) for imperfect extinction. This equation is the matrix form of Equation 6.20. We
could develop an optical system design using an ideal polarizer, and then determine design
tolerances using a more realistic one.
As an example, let us consider 5 mW of light with linear polarization at an angle ζ with
respect to the x axis, passing through ...