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Potassium
dihydrophosphates KDP (KH2PO4), DKDP
or D*KDP (KD2PO4) and ADP (NH4H2PO4)
are widely used as the second, third and fourth harmonic generators
for Nd:YAG and Nd:YLF lasers. The crystals are also widely used for
electro-optical applications as Q-switches for Nd:YAG, Nd:YLF, Ti:Sapphire
and Alexandrite lasers, as well as for Pockels cells and as for acousto-optical
applications. The most commonly used electro-optical crystal is DKDP
with a deuteration more than 98%.
These crystals are grown by a water-solution method
and can be grown up to very large sizes. Therefore, they are as low-cost
and large-size finished non-linear components available.
For frequency-doubling (SHG) and -tripling (THG) of
Nd:YAG laser at 1064 nm, both type I and type II phase-matchings can
be employed for KDP and DKDP. For frequency - quadrupling
(4HG, output at 266 nm) of Nd:YAG laser, KDP crystal is normally recommended.
We provide as-cut unpolished blocks, polished high quality KDP, ADP
and DKDP crystals in rods, squares or other shapes according
to customer's requirements.
DKDP crystals can be supplied with a deuteration level of >94%,
>96% and >98%. |
MAIN
PROPERTIES:
| |
KDP
|
DKDP
|
ADP
|
| Transparency
range, µm |
0.174 -
1.57 |
0.2 - 2.1 |
0.18 -
1.53 |
| Symmetry
class |
42m |
42m |
42m |
| Lattice
parameters, Å |
a=b=7.453;
c=6.975 |
a=b=7.469;
c=6.976 |
a=b=7.499;
c=7.549 |
| Density,
g/cm3 |
2.338 |
2.355 |
1.803 |
| Mohs
hardness |
2.5 |
2.5 |
2.0 |
| Refractive
index at 407.8 nm : |
no=1.52301;
ne=1.47898 |
no=1.5185;
ne=1.4772 |
no=1.53925;
ne=1.49123 |
|
at
632.8 nm
|
no=1.50737;
ne=1.46685 |
no=1.5044;
ne=1.4656 (at 623.4 nm) |
no=1.52195;
ne=1.47727 |
| at
1064 nm |
no=1.4938;
ne=1.4599 |
no=1.4948;
ne=1.4554 |
no=1.5071;
ne=1.4685 |
| Non-linear
coefficient at 1.064 µm, pm/V |
d36
= 0.39 |
d36
= 0.37 |
d36
= 0.47 |
| Optical
damage threshold, MW/cm2 |
300
- 600 (1064 nm, 20 ns) |
>100
(1064 nm, 20 ns) |
500
(1064 nm, 60 ns) |
The surfaces of KDP, DKDP and ADP crystals can be easily moistened.
Customers should be very careful in the maintenance of crystal surfaces.
The sealed housing is recommended for these crystals. |