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Lithium Niobate (LiNbO3) is widely used as electro-optic modulator
and Q-switch for Nd:YAG, Nd:YLF and Ti:Sapphire lasers as well as modulator for
fiber optics, etc. The transverse modulation is mostly employed for
LiNbO3 crystal.
If a
LiNbO3 with specifications listed in the following
Table is used as Q-switch crystal, i.e., the light propagates in z-axis and
electric field applies to x-axis, the refractive retardation will be
Γ=лLnr22V/λd. The electro-optic coefficients of LiNbO3 are: r33 = 32 pm/V, r31 = 10 pm/V, r22 = 6.8 pm/V at low frequency and
r33 = 31 pm/V, r31 = 8.6 pm/V, r22 = 3.4 pm/V at high electric
frequency.
LiNbO3 General specification for Q-Switch application:
| Aperture |
4x4mm ~
9x9mm |
| Length |
15~25mm |
| Tolerance of
size |
+/-0.1mm |
| Chamfer |
<0.5mm x
45° |
| Accuracy of
orientation |
<5 arc
min |
| Parallelism |
<10 arc
sec |
| Finish |
20/10
scratch/dig |
| Flatness |
l/8 at 632.8
nm |
| Electrodes |
Gold or Cr
electrode on X-faces |
| Wavefront
Distortion |
<l/4 at 632.8
nm |
| Extinction
Ratio |
>400:1 @
633nm, dia 6mm beam |
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