Biomedical Engineering Reference
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100
90
-LiNbO
3
s-polarized
shear
80
70
60
-LiNbO
3
L(010)
50
- GaP shear
40
30
20
-LiNbO
3
L(100)
10
0
1
2
3
4
5
6
7
8
9
10
Frequency (GHz)
FIGURE 3.7
Acoustic attenuation in various low-attenuation AO materials.
Figure 3.7 compares several acoustic modes which exhibit low acoustic
attenuation [14].
3.3 IntegratedOpticalBraggDevices
Bragg cell diffraction will now be described more thoroughly. The Bragg cell
diffraction efficiency (in percentage of input light deflected per watt of input
RF power) is given by [15]
2
π
λ
M
l
h
⎛
⎜
⎞
⎟
3
η
=
(3.3)
3
1
2
2
0
(
f
τ
)
0
where
λ
0
is the optical wavelength
f
0
is the center frequency of operation
τ is the AO time aperture
M
3
is the material figure of merit
l
is the normalized electrode length (and the AO interaction length)
h
is the normalized electrode height
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