Potassium dihydrogen phosphate (KH2PO4, KDP), potassium dideuterium phosphate (KD2PO4, DKDP) is one of the most widely used commercial nonlinear optical crystal materials. Despite having relatively low nonlinear optical coefficients, they exhibit strong birefringence, high damage threshold, and good UV transmittance. KDP and DKDP crystals are commonly used for doubling, tripling, and quadrupling Nd:YAG lasers at room temperature. They are also great electro-optic crystals with high electro-optic coefficients, and they are frequently employed in Q-switches and other electro-optic modulators.
Alfa Chemistry is a professional customizer of nonlinear crystals. We'll gently and carefully walk customers through the online customizing procedure for KDP and DKDP nonlinear crystals.
Advantages of KDP & DKDP Crystals
DKDP and KDP are referred to as analogs due to their properties which differ due to the deuteration of DKDP. They both have high optical damage thresholds and strong UV transmittance. These extremely birefringent crystals can be produced in vast diameters and have comparatively low nonlinearity. They also have low capacitance, a wide operating temperature range, and stable chemical and mechanical qualities. The principal disadvantage is that these crystals are extremely hygroscopic, necessitating dry operation conditions and sealed enclosures.
Fig 1. Photographs of the as-grown KDP and 70%-DKDP crystals. (Wang D, et al. 2017)
KDP and DKDP crystals of excellent quality are readily available from Alfa Chemistry for photovoltaic applications. We advise our clients to store their goods in dry (50%) and hermetically sealed enclosures. We also provide sealed housing and polishing services for KDP series crystals for this reason.
Properties of KDP & DKDP Crystals
| Basic Properties | ||
|---|---|---|
| KDP | DKDP | |
| Absorptance | 0.07/cm | 0.006/cm |
| Transparency Range | 200~1500 nm | 200~1600 nm |
| Refractive Index | (@1064nm) no=1.4938, ne=1.4599 | (@1064nm) no=1.4938, ne=1.4599 |
| Nonlinear Coefficients | d36=0.44 pm/V | d36=0.40 pm/V |
| Electro-optical Coefficients | r41=8.8 pm/V, r63=10.3 pm/V | r41=8.8 pm/V, r63=25 pm/V |
| Longitudinal Half-Wave Voltage | Vπ=7.65KV (λ=546nm) | Vπ=2.98KV(λ=546nm) |
| Optical Damage Threshold | ＞5 GW/cm2 | ＞3 GW/cm2 |
| Sellmeier Equations of KDP | no2=2.259276+0.01008956/(λ2-0.012942625)+13.00522λ2/(λ2-400) ne2=2.132668+0.008637494/(λ2-0.012281043)+3.2279924λ2/(λ2-400) | |
| Sellmeier Equations of DKDP | no2=1.9575544+0.2901391λ2/(λ2-0.0281399)-0.02824391λ2+0.004977826λ4 ne2=1.5005779+0.6276034λ2/(λ2-0.0131558)-0.01054063λ2+0.002243821λ4 | |
| Alfa Chemistry offers KDP/DKDP specification | ||
|---|---|---|
| Dimension | Upon customer request | |
| Dimension Tolerance | Dimension+0/-0.1 mm, L±0.1mm | |
| Cutting Angle Tolerance | △θ≤±0.25°,△φ≤±0.25° | |
| Flatness | λ/10 @ 632.8nm | |
| Surface Quality | 10/5 per MIL-O-13830A | |
| Clear Aperture | > 90% | |
| Damage Threshold | 750MW/cm2 at 1064nm, TEM00, 10ns, 10Hz | |
| Coating | AR/HR coating upon customer's request | |
| Quality Warranty Period | One year under proper use | |
Why Choose Alfa Chemistry?
Customers can purchase high quality KDP and DKDP nonlinear crystals from Alfa Chemistry. Sizes are customized to meet customer needs. Because their polished surfaces are more prone to wetting, we also offer polished and sealed housing services for KDP-based crystals. Our engineers will select and design the best crystal for you based on the laser parameters you provide.
Fig 2. Cutting schematic diagram of specimens for KDP and DKDP crystals. (Wang D, et al. 2016)
If you need technical advice, please contact our technical team to learn more about our high-quality services.
References
- Wang D, et al. (2017). "Research on Nonlinear Absorption Effect in KDP and 70%-DKDP Crystals." Crystals. 7(7): 188.
- Wang D, et al. (2016). "Study on Nonlinear Refractive Properties of KDP and DKDP Crystals." RSC Adv. 6: 14490-14495.