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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:
| Material |
LiNbO3
single crystal, optical grade |
| Orientation |
Parallel to X, Y,Z
axes +/-10 arc. min. |
|
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 |
| Polish Quality |
10/5
scratch/dig MIL-0-13830 |
|
Flatness |
l/10 at
632.8 nm |
|
Electrodes |
Gold
or Cr electrode on X-faces |
|
Wavefront Distortion |
<l/4
at 632.8 nm |
| Clear Aperture |
central 90% |
| Chamfers |
0.2-0.3 mm @ 45 deg |
| AR coating |
R< 0.2 % per surface
at 1064 nm
( other wavelengths are available on
request) |
| Optical Damage
Threshold |
> 200 MW/cm2
at 1064 nm, 10-20 ns pulse length
Halfwave Voltage at 632.8 nm: ~ 4000
V · A/L |
|
Extinction Ratio(Optical Grade) |
>400:1 @ 633nm, dia 6mm beam |
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