Potassium Dihydrogen Phosphate
Potassium Dideuterium Phosphate
(KDP, DKDP or KD*P) KH2PO4 KD2PO4
KDP, DKDP or KD*P

Potassium Dihydrogen Phosphate (KDP) and Potassium Dideuterium Phosphate (DKDP) are nonlinear optical materials (NLO)know for their large NLO coefficients, wide transparency range and high optical damage threshold.

 

These materials are widely used as frequency multipliers for generation of the second, 
third and fuorth harmonics for Nd:YAG, Nd:YLF lasers. Both crystals are also applied in electro-optics: 
as Q-switches for Nd:YAG, Nd:YLF, Ti:sapphire and Alexandrite lasers and Pockels cells.

 

Owing to a posibility of growing large crystals, high laser frequency multipliers. Q-switches and Pockels cells, laser damage threshold of witch is over 40 J/cm2 (at lambda=1,06 µm, tau=3 ns). This allows to use them in the devices for laser fusion.

 

KDP and DKDP crystals possess elctro-optical, nonlinear and piesoelectric properties, high laser damage threshold and are used as the base for the devices and systems of laser engineering: frequency multipliers, modulators, gates, deflectors.

 

 

Basic Properties45

KDP

DKDP

Chemical Fomula

KH2PO4

KD2PO4

Class of symmetry

42m

42m

Crystal structure

tetragonal

tretagonal

Transparency Range, mm

0,2 – 1,5

0,2 – 1,6

Wafelength range, nm

200-1500

2

Electro – optical Coefficients, pm/V-1.

r41 = 8.8
r63 = 10.3

r41 = 8.8
3 = 25

Nonlinear Coefficients

d36 = 0.44 pm/V

d36 = 0.40 pm/V

Refractive index (at 1064 nm)

n0 = 1.4938 
nc = 1.4599

no = 1.4948
nc = 1.4554

Temperature Synchronism Width, oC*cm

11,5.

7,4.

Spectral Synchronism Width, A

*cm

106

Angle Synchronism Width, mrad*cm

0,84

0,94

Longitudinal half-wave voltage

Vn = 7.65 KV 
(l = 546 nm)

Vn = 2.98 KV 
(l= 546 nm)

Absorpion Coefficient, cm-1

0.07

0.006

Optical Damage Threshold
(l=1,064 mm, t=10ns)

>5 GW / cm²

>3 GW / cm²

ohs Hardness

2,5

2,5

Extinction ratio

 

30 dB

Sellmeier equations of DKDP

n02 = 1.9575544 + 0.2901391 l2 / (l2 – 0.0281399) – 0.02824391 l2 + 0.004977826 l2

nc2 = 1.5005779 + 0.6276034 l2 / (l2 – 0.0131558) – 0.01054063 l2 + 0.002243821 l4

Sellmeier equations of KDP

n02 = 2.259276 + 0.01008956 / (l2 – 0.012942625) + 13.00522 l2 / (l2 – 400)

nc2 = 2.132668 + 0.008637494 / (l2 – 0.012281043) + 3.2279924 l2 / (l2 – 400)

Refractive  Indix

Sellmeier Equation

n2 = A + B   /   (l2 – C) + Dl2   /    (l2 – E)    ( l in mm )

Sellmeier Coeficients

KDP

KD*P

ADP

CDA

CD*A 

A

no

2.2576

2.2409

2.3041

0.4204

2.4082

 

ne

2.1295

2.1260

2.1643

2.3503

2.3458

B

no

0.0101

0.0097

0.0111

0.0163

0.0156

 

ne

0.0097

0.0086

0.0097

0.0156

0.0151 

C

no

0.0142

0.0156

0.0133

0.0180

0.0191

 

ne

0.0014

0.0120

0.0129

0.0168

0.0168 

D

no

1.7623

2.2470

15.1086

1.4033

2.2122

 

ne

0.7580

0.7844

5.8057

0.6853

0.6518 

E

no

57.8984

126.9205

400.0000

57 8239

126.8709

 

ne

127.0535

123.4032

400.0000

127.2700

127.3309 

 

l = 1064

no

1.4942

1.4931

1.5071

1.5515

1.5499

Typical
Values

nm

ne

1.4603

1.4583

1.4685

1.5356

1.5341 

 

l = 532

no

1.5129

1.5074

1.5280

1.5732

1.5692

Typical
Values

nm

ne

1.4709

1.4683

1.4819

1.5516

1.5496 

 

l = 355

no

1.5317

1.5257

1.5487

1.6026

1.5974

 

nm

ne

1.4863

1.4833

1.4994

1.5788

1.5759