| Introduction
Potassium Titanyle Arsenate(KTiOAsO4), or KTA crystal,
is an excellent nonlinear optical crystal for  Optical Parametric Oscillation (OPO) Application.
OPO devices based on KTAs are reliable, solid state sources
of tunable laser radiation exhibiting energy conversion
efficiencies above 50%. In addition KTA has a very high
damage threshold.
In comparison to KTP, KTA crystals feature large non-linear
optical and electro-optical coefficients and have significantly
reduced absorption in the 2.0 - 5.0 m range. Its low dielectric
constants, low loss tangent and ionic conductivities are
orders of magnitude less than that of KTP.
Advantage:
 Large nonlinear optical and electro-optical
coefficients
Wide angular bandwidth and small
walk-off angle
Broad temperature and spectral
bandwidth
Low dielectric constants, loss
tangent and ionic conductivities (much less than that of
KTP)
High damage threshold
Lower absorption in the 3-4 µm
spectrum range than KTP.
Highly resistant to high intensity
laser radiation.
Application:
An excellent NLO crystal developed
mainly for Optical Parametric Oscillation (OPO)
Frequency Doubling (SHG @1083nm-3789nm)
Sum and Difference Frequency
Generation (SFG)/(DFG)
Electro-Optical Q-switch and
modulation for Optical waveguides
Physical and Chemical
Properties:
| Formulation |
KTiOAsO4 |
| Crystal
structure |
Orthorhombic |
| Lattice
parameters |
a=13.125 b=6.5716
c=10.786 |
| Point group |
mm2 |
| Hardness
(Mohs) |
near 5 |
| Hygroscopic
susceptibility |
none |
| Chemically |
stable |
| Melting Point |
1130±5°C |
| Ferroelectric transition
temperature (°C) |
880°C |
| Density |
3.454 g/cm3 |
| Hygroscopic susceptibility |
No |
| Dielectric constant: |
ε33=42 |
| Thermal conductivity
(mw/cm°C) |
k1=18, k2=19, k3=21 |
| Thermal
conductivity
(mW/cm/k) |
|
| Ionic conductivity
(room temperature, 10kHz) |
0.7 - 3.4.10-6 S/cm |
| Absorption |
@ 1064 nm
<0.05 %/cm
@ 1533 nm <0.05 %/ cm
@ 3475 nm <5%/cm |
Optical Properties:
| Transmitting range: |
0.35-5.3um |
| Refractive
indices(@ 1064 nm):
|
nx=1.782 |
| ny=1.790, |
| nz=1.868, |
| Sellmeier equations:
Ni^2=Ai+Biλ^2/(λ^2-Ci^2)-Diλ^2 |
index |
A |
B |
C |
D |
| Nx |
1.90713 |
1.23522 |
0.19692 |
0.01025 |
| Ny |
2.15912 |
1.00099 |
0.21844 |
0.01096 |
| Nz |
2.14768 |
1.29559 |
0.22719 |
0.01436 |
| Phase matching range(nm): |
1075-1134nm |
| Nonlinear Coefficients:
(pm/v) |
d15 =2.3, d24 =3.2, d31 =2.8, d32 =4.2, d33 =16.2 |
| damage threshold(10
ns pulse): |
15J/cm^2 at 1064 nm |
| NCPM Angle |
|
| Wavelength |
| Pump |
Signal |
Idler |
| 1064
nm |
1533
nm |
3475
nm |
|
| Electro-optical
constants
(low frequency) |
| r33 |
r23 |
r13 |
| 37.5
pm/V |
15.4
pm/V |
11.5
pm |
|
Specification
| Dimension
tolerance: |
±0.1mm |
| Flatness: |
<l/8 @633nm |
| Surface
quality: Scratch/Dig |
10/5 |
| Parallelism:
|
better than 30 arc sec. |
| Perpendicularity: |
better than 30 arc min |
| Angle
tolerance: |
△q
< 0.5°,△f
< 0.5°
|
| AR
coating: |
AR
coatings
|
| Clear
aperture: |
>90% central area |
| Transmitting
wave front distortion: |
less than l/8 @ 633nm |
|
