Potassium Dihydrogen Phosphate (KDP)

Short Description:

Potassium Dihydrogen Phosphate (KDP) and Potassium Dideuterium Phosphate (DKDP, KD*P) are among the most widely-used commercial NLO materials. 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, Q-switches, and Pockels Cells, etc.

Product Detail

Product Tags


● Second, third, and fourth harmonic generation of Nd:lasers;

● Frequency doubling of Dye Laser;

● Frequency Conversion of high power lasers;

● Shutter for high speed photography;

● Electro-optical Modulator, Q-switches, Shutter for high speed photography.

Physical and Optical Properties

Crystal Structure Tetragonal, space group D4h Tetragonal, space group D4h
Lattice Parameters (Å) a=7.4529, c=6.9751 a=7.4697, c=6.9766
Curie point (°C) ~396 ~495
Mohs Hardness ~2.5 ~2.5
Density (gram/cm3) 2.332 2.355
Hygroscopic Susceptibility high high
Thermal Conductivity (W/cm/K) k11= 1.9 x 10-2 k11= 1.9 x 10-2
k33= 2.1 x 10-2
Thermal Expansion Coefficients (K-1) a11= 2.5 x 10-5 a11= 1.9 x 10-5
a33= 4.4 x 10-5 a33= 4.4 x 10-5
Resistivity (ohm • cm) 10-20 x 106 10 x 106
Relative Dielectric Constant (@ 25°C and 1KHz) εT11/ε0= 43.2,εs11/ε0=42.5 εT11/ε0= 65.0,εs11/ε0= 62.5
εT33/ε0=20.8,εs33/ε0=20.0 εT33/ε0= 50.0,εs33/ε0= 48.0

Optical and Nonlinear Properties

                    KDP                       DKDP
Transparency Range                 180-1500nm                    200-2100nm
Electro-Optics Coefficients (pm/V)              r41=8.8, r63=10.3                  r41=8.8, r63=25
Refractive Index @ 1064nm         no=1.4938, ne=1.4599            no=1.4948, ne=1.4554
Sellmeier Equations of KDP
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 DKDP
no2 = 1.9575544 + 0.2901391/(λ2- 0.0281399) - 0.02824391λ2 +0.004977826λ4
ne2 = 1.5005779 + 0.6276034/(λ2 - 0.0131558) - 0.01054063λ2 +0.002243821 λ4
Effective Nonlinear Optical Coefficient @ 1064nm (pm/V)                  d36=0.44                        d36=0.40


Dimension tolerance  (W +/-0.1mm)x(H+/-0.1mm)x(L+0.2mm/-0.1mm)
Wavefront distortion  Less than λ/8 @ 633nm
Clear auperture  >90% central area
Flatness  λ/8 @ 633nm
Surface Quality  10/5 Srcatch/Dig
Parallelism  better than 20 arc seconds
Perpendicularity  5 arc nimutes
Angle tolerance  theta delta<0.3 deg, phi delta<0.3 deg
Quality Warranty Period  3 month under proper use

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