Introduction
Lithium
niobate is a ferroelectric material suitable for a variety
of applications. Its versatility is made possible by the
excellent electro-optic, nonlinear, and piezoelectric properties
of the intrinsic material. It is one of the most thoroughly
characterized electro-optic materials, and crystal growing
techniques consistently produce large crystals of high perfection.
Applications that use the large nonlinear
d coefficient of LiNbO3 include
optical parametric oscillaton, difference frequency mixing
to generate tunable infrared wavelengths, and second harmonic
generation. With a broad spectral transmission, which ranges
from 0.4 µm to 5.0 µm with an OH- absorption at 2.87 µm,
a large negative birefringence, and a large nonlinear coefficient,
phasematching is an effective way to generate tunable wavelengths
over a broad wavelength range.
Lithium niobate is particularly effective
for second harmonic generation of low power laser diodes
in the 1.3 to 1.55 µm range.
For infrared generation by difference frequency
mixing, the peak power limit is considerably lower than
for 1.064 µm, being about 40 MW/cm2Efficiencies
for difference frequency mixing generally are smaller than
shg efficicncies with KDP or BBO, which is due to the lower
peak powers that can be tolerated by the crystal and the
fact that the longer wavelength photons that are generated
in the process are less energetic.
Physical and Chemical Properties:
Please view NLO crysals physical Properities (dpf format)
The Sellmeier equations (l in µm ):
no2 = 4.9048 + 0.11768/(l 2-0.04750)-0.027169l 2
ne2 = 4.5820 + 0.099169/(l 2-0.04443)-0.021950l 2
Optical and Spectral Properties
Please view NLO crysals optical and nonlinear optical Properities (dpf format)
he Fe:LiNbO3 and MgO:LiNbO3
crystals is available too. The MgO: LiNbO3 has similar effective
nonlinear coefficients to pure LiNbO3. Its Sellmeier equations (for MgO dopant
7 mol%) are:
no2
= 4.8762+ 0.11554/(l
2-0.04674)-0.033119l
2
ne2 = 4.5469+ 0.094779/(l
2-0.04439)-0.026721l
2
LiNbO3’s Specifications
Material: |
Laser
grade LiNbO3 |
Orientation: |
±0.5
o |
Dimensional
Tolerance:
|
±0.1mm |
Surface
quality:
|
20/10
Scratch/Dig per MIL-O-13830B |
Flatness:
|
l/8
at 633 nm
|
Perpendicularity:
|
5
arc min |
Parallelism: |
better
than 20 arc sec
|
Clear
Aperture:
|
> Central 90%
|
AR
Coating:
|
AR
coating with R < 0.2% at center wavelength |
|