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KDP (Potassium Dihydrogen Phosphate) and
KD*P
(Potassium Dideuterium Phosphate)
KDP and KD*P are among the most widely-used commercial NLO
materials, characterized by good UV transmission, high damage threshold, and high
birefringence. They are commonly used for doubling, tripling and quadrupling of Nd:YAG laser at the room temperature. In addition, they are also excellent electro-optic
crystals with high electro-optic coefficients, widely used as electro-optical modulators and Pockels
cells for Q-switched lasers.
Please
contact us for your need of KDP or KD*P crystals.
Physical and Optical Properties
|
|
KDP |
KD*P(DKDP) |
|
Chemical
Formula |
KH2PO4 |
KD2PO4 |
|
Crystal
Structure |
Tetragonal |
Tetragonal |
|
Transmission
Range |
200-1500nm |
200-1600nm |
|
Nonlinear
Coefficients |
d36=0.44pm/V |
d36=0.40pm/V |
|
Refractive
Indices
(at 1064nm) |
no=1.4938,
ne=1.4599 |
no=1.4948,
ne=1.4554 |
|
Electro-Optical
Coefficients |
r41=8.8pm/V
r63=10.3pm/V |
r41=8.8pm/V
r63=25pm/V |
|
Longitudinal
Half-Wave Voltage |
Vp=7.65KV(λ=546nm)
|
Vp=2.98KV(λ=546nm) |
|
Absorption |
0.07/cm |
0.006/cm |
|
Temperature
Acceptance |
11.5
oC*cm |
7.4
oC*cm
|
|
Spectral
Acceptance |
106 Å*cm |
32 Å*cm |
|
Angular Acceptance |
0.84 mrad*cm |
0.94 mrad*cm |
|
Absorption Coefficient
( cm-1) |
0.07 |
0.006 |
|
Mohs Hardness
|
2.5 |
2.5 |
|
Optical Damage Threshold |
>5 GW/cm2 |
>3 GW/cm2 |
|
Extinction
Ratio |
30dB |
30dB |
|
Sellmeier Equations of
KDP
(λ in µm) |
no2
= 2.259276 + 0.01008956/(λ2 -
0.012942625) +
13.005522λ2/(λ2 - 400)
ne2 = 2.132668 + 0.008637494/(λ2-
0.012281043) +
3.2279924λ2/(λ2 - 400) |
Sellmeier Equations of
KD*P
(λ in µm) |
no2 = 1.9575544 + 0.2901391/(λ2 -
0.0281399) -
0.02824391λ2 +0.004977826λ4
ne2 = 1.5005779 + 0.6276034/(λ2 -
0.0131558) -
0.01054063λ2 +0.002243821λ4 |
Cut Orientations for KDP/KD*P Crystal
|
Process (PM type) |
KDP |
KD*P |
|
Orientation |
Deff(pm/V) |
Orientation |
Deff(pm/V) |
|
SHG (II): 1064 nm -> 532 nm
|
58.9 |
0.34 |
53.5°
|
0.34 |
|
THG (II): 1064+532 -> 355 nm |
58.4 |
0.37 |
59.4° |
0.33 |
|
SFG (II): 1064+(421-1000
nm) -> 302-515 nm |
61.0 |
0.36 |
63.7° |
0.31 |
|
FHG (I): 532 nm -> 266nm |
76.7 |
0.46 |
85.9° |
0.43 |
|
NCPM FHG (I): 532 -> 266 nm |
90°(T=250°C) |
0.47 |
90°(T=55°C) |
0.43 |
|
SHG (I): 1064 nm -> 532 nm |
41.1 |
0.26 |
36.6° |
0.22 |
|
THG(I): 1064+532 -> 355 nm |
47.4 |
0.32 |
46.8° |
0.29 |
Specifications on finished crystals
|
Wavefront
distortion:
|
less than
λ/8 @ 633nm
|
|
Dimension
tolerance:
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(W ± 0.1mm) x (H ± 0.1mm) x (L +
0.2mm/-0.1mm)
|
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Clear aperture:
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> 90% central
area
|
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Flatness:
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λ/8 @ 633nm
|
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Surface Quality:
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Scratch/Dig
10/5 per
MIL-O-13830A
|
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Parallelism:
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better than 20
arc seconds
|
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Perpendicularity:
|
5 arc minutes
|
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Angle tolerance:
|
Δθ <
+/-0.5 deg, Δφ <
+/-0.5 deg |
 Coating
KDP,
KD*P are highly hygroscopic and typically sold as an uncoated crystal sealed
in a housing with AR coated windows (shown at right).
High damage threshold oxide coatings directly applied on KDP, KD*P are
available upon request.
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