KDP & DKDP Crystals
What Are KDP/DKDP Crystals?
KDP (potassium dihydrogen phosphate, KH2PO4) is a synthetic, water-soluble crystal. DKDP (deuterated potassium dihydrogen phosphate, KD2PO4 or KD*P) is its deuterated version, where hydrogen is replaced by deuterium. They are widely used in second-, third-, and fourth-harmonic generation of Nd:YAG and Nd:YLF lasers, as well as in electro-optical applications such as Q-switching, Pockels cells, and acousto-optic applications.
KDP crystals have high optical transmittance and good nonlinear coefficients, making them an important material for electro-optical components in various pulsed lasers.
Features
- Excellent Non-linear Optical Properties: Efficient for frequency conversion (e.g., Second and Third Harmonic Generation - SHG/THG).
- High Electro-optic Coefficient: Their refractive index changes under an electric field, useful for modulating light.
- High Laser Damage Threshold: Especially DKDP, which can withstand high-power laser pulses.
- Wide Transparency Range: From UV to near-IR (200~2100nm).
- Piezoelectric Properties: Can generate an electric charge under mechanical stress.
- Easy to Grow: Can be grown to large sizes, which is critical for high-power laser systems.
SpecificationApplications
| Product Name | KDP Crystal | DKDP Crystal |
| Catalog No. | OPTIX-0001 | OPTIX-0002 |
| Chemical Formula | KH2PO4 | KD2PO4 |
| Crystal Structure | Tetragonal System, 42m | Tetragonal System, 42m |
| Lattice Parameters | a=7.448 Å, c=6.977 Å | a=7.4697 Å, c= 6.966 Å |
| Optical Symmetry | Negative Uniaxial (no > ne) | Negative Uniaxial (no > ne) |
| Density | 2.338 g/cm3 | 2.355 g/cm3 |
| Mohs Hardness | 2.5 | 2.5 |
| Transmittance Range | 180nm~1550nm | 200nm~2150nm |
| Refractive Index | no =1.4938; ne =1.4599 @1064nm | no = 1.4948; ne = 1.4554 @1064nm |
| Orientation Accuracy | < 30 arcmin | < 30 arcmin |
| Clear Aperture | >90% | >90% |
| Parallelism | <20 arcsec | <20 arcsec |
| Perpendicularity | ≤5 arcmin | ≤5 arcmin |
| Surface Quality | 20/10, S/D | 20/10, S/D |
| Flatness | <λ/4 @ 632.8nm | <λ/4 @ 632.8nm |
| Optical Damage Threshold | >5 GW/cm2, @ 1064nm 10ns | >3 GW/cm2, @ 1064nm 10ns |
| Extinction Ratio | 30dB | 30dB |
| Electro-Optical Coefficient | Y41=8.8 pm/V; Y63= 10.3 pm/V | Y41=8.8 pm/V; Y63= 25 pm/V |
| Nonlinear Coefficient | d36=0.44 pm/V | d36=0.40 pm/V |
Note: The data provided is for reference purposes. We recommend consulting with our technical team to verify suitability for your application.
- Laser Frequency Conversion: Doubling or tripling the frequency of lasers (e.g., converting 1064 nm IR light to 532 nm green or 355 nm UV light).
- Electro-optic Modulators (Pockels Cells): Used as optical switches/Q-switches in lasers to generate powerful pulses.
- Piezoelectric Devices: Used in sensors and transducers.
KDP vs. DKDP: How to Choose?
| Feature | KDP Crystal | DKDP Crystal |
| Primary Strength | Cost-effective solution for many NLO/EO applications | Superior laser damage threshold (LDT) and performance at high powers |
| Best For | EO modulators, Q-switches, frequency conversion where extreme power isn't a factor | High-power/energy harmonic generation (e.g., THG for 355nm), large-aperture systems for fusion research |
| Deuteration Level | N/A | Standard (e.g., >95%) or custom levels available to optimize for specific wavelengths |
Why Choose Alfa Chemistry?
- Decades of Expertise: Our mastery of crystal growth and fabrication is unmatched.
- Rigorous Quality Control: Every crystal undergoes extensive inspection to ensure it meets our strict standards for optical homogeneity, wavefront distortion, and damage threshold.
- Full Customization: We provide solutions, not just products. Tell us your needs, and we will engineer a crystal to meet them.
- Global Support & Technical Service: Our team of experts is ready to support you from the design phase through integration and beyond.
