Description
Introduction
Potassium Dihydrogen Phosphate (KDP) and Potassium Dideuterium Phosphate (DKDP) are among the most widely-used commercial NLO materials, characterized by good UV transmission, high damage threshold, and high birefringence, though their NLO coefficients are relatively low. They are usually used for doubling, tripling, and quadrupling of a Nd:YAG laser under room temperature. In addition, they are also excellent electro-optic crystals with high electro-optic coefficients, widely used as electro-optical modulators, such as Q-switches, Pockels Cells, etc.
Because their polished surfaces are easier to moisten, the user is advised to provide the dry condition (＜50%) and the sealed housing for preservation. For this purpose, we also provide polishing, coating, and sealed housing services for the KDP family crystals. Our engineers will serve you to select and design the best crystal, according to the laser parameters you provide.
Table 1. Basic Properties
| DKDP | KDP | |
| Chemical Formula | KD2PO4 | KH2PO4 |
| Transparency Range | 200-2100 nm
(98% deuterium content) |
200-1650 nm |
| Nonlinear Coefficients | d36 = 0.40 pm/V | d36 = 0.44 pm/V |
| Refractive Index (at 1064 nm) | no = 1.4948, ne = 1.4554 | no = 1.4938, ne = 1.4599 |
| Electro-optic Coefficients | r41 = 8.8 pm/V
r63 = 25 pm/V |
r41 = 8.8 pm/V
r63 = 10.3 pm/V |
| Longitudinal Half-wave Voltage | Vπ = 2.98 KV (λ = 546 nm) | Vπ = 7.65 KV (λ = 546 nm) |
| Absorption Coefficients | 0.006 /cm | 0.07 /cm |
| Damage Threshold | >3 GW/cm2 | >5 GW/cm2 |
| Extinction Ratio | 30 dB | |
| Sellmeier Equations of DKDP: (λ in µm) | ||
| no2 = 1.9575544 + 0.2901391 λ2 / (λ2 – 0.0281399) – 0.02824391 λ2 + 0.004977826 λ4
ne2 = 1.5057799 + 0.6276034 λ2 / (λ2 – 0.0131558) – 0.01054063 λ2 + 0.002243821 λ4 |
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| Sellmeier Equations of KDP: (λ in µm) | ||
| no2 = 2.259276 + 0.01008956 / (λ2 – 0.012942625) + 13.00522 λ2 / (λ2 – 400)
ne2 = 2.132668 + 0.008637494 / (λ2 – 0.012281043) + 3.2279924 λ2 / (λ2 – 400) |
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Coatings
AR-Coatings are available with high quality upon request.
