5
0
-90¡ã
B
D
α+α'
C
A
+90¡ã
t
B'
t
D'
C'
t
t
图1
α+α'
α'
β
β
β
β
β
β
When the both ends of Faraday ring is connected to a frequency of f sinusoidal alternating voltage
(u = Usin2
π
ft), according to the Faraday Magneto-optical Effect, the vibration plane which the
plane-polarized light goes through will add an additional angle of rotation:
α
1 =
β
• sin2
π
ft. When
there is a Faraday ring between the polariser and the analyzer, the intensity signal of emission light
from analyzer is as below:
a)
In the quadrature position, the curve B and B' in Figure 1 can be obtained. The light intensity
signal is the superposition of the light intensity of a constant frequency and a 2f alternating light
intensity.
b)
When the quadrature position is deviated from the right, the curve C and C' in Figure 1 can be
obtained. The light intensity signal is the superposition of the light intensity of a constant frequency
and a 2f alternating light intensity, see curve C'.
c)
When deviating from the quadrature position leftward, the curve D and D ' in Figure 1 can be
obtained. The light intensity signal is the superposition of the light intensity of a constant frequency
and a 2f alternating light intensity, see curve D'. However, the phase of the alternating light
intensity is just the opposite of alternating light intensity signals when deviating from the
quadrature position.
Therefore, identify whether the alternating light intensity of the f component in signal intensity is
Figure 1
