KDP and KD*P
Potassium Dihydrogen Phosphate (KDP) and Potassium Dideuterium Phosphate (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.
- Good UV transmission
- High optical damage threshold
- High birefringence high nonlinear coefficients
Physical and Optical Properties
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KDP
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KD*P
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Chemical Formula |
KH2PO4
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KD2PO4
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Crystal Structure |
Tetragonal
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Teragonal
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Transmission Range |
200-1500nm
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200-1600nm
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Nonlinear Coefficients |
d36 = 0.44pm/v
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d36 = 0.04pm/v
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Refractive Indicies (@ 1064nm) |
no = 1.4938
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ne = 1.4599
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no = 1.4938
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ne = 1.4599
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Electro-Optical Coefficients |
r41 = 8.8pm/v
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r63 = 10.3pm/v
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r43 = 8.8pm/v
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r63 = 25pm/v
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Longitudinal Half-Wave Voltage |
Vp = 7.56KV (1 = 546nm)
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Vp = 2.98KV (1 = 546nm)
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Absorption |
0.07/cm
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0.006/cm
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Temperature Synchronism Width |
11.5°C·cm
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7.4°C·cm
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Spectral Synchronism Width |
106°·cm
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32°·cm
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Angle Synchronism Width |
0.84mrad·cm
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0.94mrad·cm
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Absorption Coefficient , cm-1 |
0.07
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0.006
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Mohs Hardness |
2.5
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2.5
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Optical Damage Threshold |
> 5GW/cm2
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> 3GW/cm2
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Extinction Ratio |
.
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30dB
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Sellmeir Equations for 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)
Sellmeir Equations for KD*P:
no2 = 1.9575544 + 0.2901391 / (λ2 – 0.0281399) – 0.02824391λ2 + 0.004977826λ4
ne2 = 1.5005779 + 0.6276034 / (λ2 – 0.0131558) – 0.01054063λ2 + 0.002243821λ4
Application:
- Second, third, and fourth harmonic generation of Nd:lasers
- Frequency doubling of dyer laser
- High power laser frequency conversion materials
- Shutter for high speed photography
- Electro-optical modulator and Q switches
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KD*P Single Crystal Standards
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Designation
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Operation
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Input
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Output
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53.7°
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SHG (II)
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1064nm
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532nm
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59.5°
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THG (II)
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1064nm + 532nm
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355nm
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63.7°
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SFM (II)
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1064nm + (421-1000nm)
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302 – 515nm
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86°
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FHG (I) angle tune
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532nm
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266nm
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90°
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FHG (I) temperature tune
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532nm
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266nm
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36.6°
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SHG (I)
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1064nm
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362nm
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46.8°
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THG (I)
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1064nm + 352nm
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355nm
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KDP and KD*P Specifications
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Wavefront Distortion: |
< 8 @ 633nm |
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Dimension Tolerance: |
(W ± 0.1mm)x(H ± 0.1mm)x(L +0.2mm/ -0.1mm) |
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Clear Aperture: |
> 90% central area |
| Flatness: | λ /8 @633nm |
| Surface Quality: | 10/5 to MIL-O-13830A |
| Parallelism: | Better than 20 arc seconds |
| Perpendicularity: | 5 arc minutes |
| Angle Tolerance: |
Δθ < 0.3° , Δφ < 0.3° |
| Quality Warranty Period: | One year under proper use |