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Barium Titanate (BaTiO3
)
Barium Titanate single crystal is an excellent photorefractive material which
has high SPPC (Self pumped Phase Conjugation) reflection and two wave mixing
(optical amplification) efficiency, It is important for information processing
and image storage. Besides that it is also an important substrate material for
some special film as its unique ferroelectric and other properties.
Followings are
important for the use of BaTiO3, both for the bulk device and
substrate:
1.The tetragonal
BaTiO3 single crystal (the useful phase for both photorefractive
effect and substrate) will change the phase when its temperature is lower than
13℃ or higher 125℃,
so it is necessary to keep its temperature in the safe range during its using,
storage and transportation.
2.The extra
force such as compacting, cracking will cause a phase transition.
3.Poling is
needed for (001)orientation substrate, while is not necessary for
（100）、（110）、（111）orientations.
4.Normally the
maximum size for BaTiO3 substrate is 10x10mm; the thinnest thickness
is 0.3mm.
Typical Properties:
|
Crystal
Structure |
Tetragonal(4m) 13oCoC |
|
Cell
parameter |
a=3.99Å,c=4.04Å,(at
26 oC) |
|
Melting
Point |
1891
oK |
|
Density
|
6.06 g/cm3 (at 26 oC) |
|
Specific
Heat |
0.527J/g.k(300oK) |
|
Thermal
conductivity |
6
W/m.k(300oK) |
|
Thermal
expansion
(10-6k-1) |
15.7∥a 6.2∥c |
|
Dielectric constant（εr） |
Ea=3000 εc=800 |
|
Hardness（Mohs） |
4.5 |
|
Growth
Method |
TSSG(Top
Seeded Solution Growth) |
|
Index of
Refraction |
|
515 nm |
633 nm
|
800 nm |
|
no
|
2.4912 |
2.4160 |
2.3681
|
|
ne
|
2.4247 |
2.3630 |
2.3235
|
|
Transmission wavelength |
0.43 -
6.30
um
|
|
Electro
Optic
Coefficients |
rT13=8+/-2
pm/V
rT33=105-/+10
pm/V
rT42=
1300+/-100 pm/V |
|
Reflectivity of SPPC
( at 0
deg. cut ) |
50-70
% (Ce: BaTiO3) for lamda = 515 nm
40-60%
(PureBaTiO3) for lamda = 515 nm
50-80
% (Ce: BaTiO3) for lamda = 633 nm
40-60% (PureBaTiO3) for lamda = 633 nm |
|
Two-wave
mixing coupling constant |
10-40
cm-1 |
|
Absorption loss |
Lamda:
515 nm 633 nm 800 nm
a :
0.285cm-1 0.108cm-1 0.033cm-1
|
|
Wavelength range for photo refractive effect |
Undoped
BTO :for visible
Ce:BTO:480-780nm
Rh:BTO:720-1060nm |
Specifications:
Standard Size: 10x10，10x5,5x5
mm,
Thickness:
0.5mm，1.0mm.
Polishing: one or two side polished
Bulk: 5x5x5,4x4x4,3x3x3 mm, 0oor 45ocut,2-6 faces polished
Orientation：＜100＞,
＜110＞,
＜001＞,
＜111＞
Orientation
accuracy:
+/-0.5o
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