Lithium Niobate Crystal LiNbO3
LiNbO3 is one of the most attractive materials for optoelectronics. A great
variety of devices has been developed based upon this material having unique
electro-optical, photoelastic, piezo-electric and non-linear properties combined
with good mechanical and chemical stability and wide transparency range.
ELAN offers a lot of products made of high quality LiNbO3 crystals of both
Acoustical and Optical grades. Typically, Czochralsky grown and poled along
Z-axis boules are used with sizes up to 80 nm in dia. and 100 mm in length.
Other boules orientations can be applied for some purposes (SAW surstrates,
piezotransducers).
Material propeties
| Crystal symmetry |
Trigonal, 3m |
| Lattice constant, A |
a = 5.148 c = 13.863 |
| Density, g/cm3 |
4.64 |
| Melting point , °C |
1255 |
| Curie point , °C |
1142 |
| Mohs hardness |
5 |
| Solubility |
Insoluble in water |
| Color |
Colorless |
| Thermal expansion coefficient, 10-6/ °C |
aa = 15 ac = 5 |
| Specific heat, cal/g°C |
0.15 |
| Thermal conductivity , mW/cm °C |
46 |
| Dielectric Constant (@ 100 KHz) |
ea =
85 ec = 29 |
| Transparency range, nm |
350 - 550 |
| Refractive indices @ 633 nm |
no = 2.29 ne = 2.20 |
Electro-optic coefficients
pm/V @633 nm, high frequency |
r33 = 31
r13 = 9
r22 = 3.4 |
Nonlinear optical coefficients
p/m/V @ 1064 nm |
d22 = 2.1
d31 = - 4.5
d33 = -0.27 |
| Optical damage threshold |
250 MW/cm2 @ 1064 nm, t ~ 10nsec. |
| Optical homogeneity |
~10-5 |
| Absorption loss @ 1064 nm |
< 0.1
%/cm |
NOTE
- Above data are valid for congruent grown crystal (48.6 mol.% Li2O), at
20°C .
- LiNbO3 damage due to photorefractive effect in congruent melt grown LiNbO3
certainly limits it's applications in high optical power devices. For this
purpose specially grown LiNbO3 with composition near stoichiometric can be
offered. It is similar to the Li-rich VTE LiNbO3 with the obvious advantage that
bulk samples can be obtained. Another possibility to increase laser damage
threshold of LiNbO3 is doping with MgO. ELAN can offer both MgO:LiNbO3 and
stoichiometric LiNbO3 elements cut from boules up to 60 mm dia.
- Some other crystals of LiNbO3 series are available, including LiNbO3 doped
with Fe, Zn, Gd, Cu , Y, B, Er etc.
- For some applications similar in properties LiTaO3 crystal is more
advantageous than LiNbO3 (E-O modulators, pyroelectric sensors etc.). ELAN can
offer parts cut from high quality boules grown along X axis, fully poled, with
dia. and length up to 60 mm.
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