Specifications:
| Material | ZnGeP2 | Thickness Tolerance | +/-0.05mm |
| Orientation Tolerance | <0.5° | Flatness | less than λ/8 @ 633nm |
| Transmitting Wavefront Distortion | less than λ/4 @ 633nm | Chamfer | ≤0.2mmx45° |
| Chip | ≤0.1mm | Surface Quality | better than 10/5 S/D (MIL-PRF-13830B) |
| Parallelism | ≤30 arc seconds | Perpendicularity | ≤15 arc minutes |
| Aperture | >90% | ||
Chemical and Physical Properties:
| Chemical Formula | ZnGeP2 | Crystal Structure | Tetragonal, 42m |
| Lattice Parameter | a=b=5.467Å, c=12.736Å | Mass Density | 4.16 g/cm3 |
| Moh Hardness | 5.5 | Melting Point | About 1040°C |
| Thermal Conductivity | 180 W/m/K | Thermal Expansion Coefficient | β,5x10-6 /K; β⊥,7.8x10-6 /K |
| Birefringence | Positive uniaxial | ||
Linear Optical Properties
| Transparency range | 0.74 - 12μm |
| Absorption coefficient | α<0.05cm-1 @2050-2100nm |
| Refractive Indices @ 2.05 μm @ 2.79 μm @ 5.30 μm @ 10.6 μm |
no = 3.1478, ne = 3.1891 no = 3.1333, ne = 3.1744 no = 3.1136, ne = 3.1547 no = 3.0729, ne = 3.1143 |
| Sellmeier Equations(λ in μm) | no2(λ) = 4.64467+5.10087/(λ2-0.13656)+4.27777λ2/(λ2-1653.89) ne2(λ) = 4.71539+5.26358/(λ2-0.14386)+2.37310λ2/(λ2-1000.82) |
Nonlinear Optical Properties
| SHG Phase Matchable | 3177 ∼ 10357nm (Type I) |
| NLO coefficients | d36=75 ± 8 pm/V Type Ⅰ deeo=d36 sin2ϴcos2φ Type Ⅱ doeo=deoo=d36 sinϴsin2φ |
| Damage Threshold | |
| at 2.79 μm | 30 GW/cm2 (150 ps) |
| at 10.6 μm | 1 GW/cm2 (2 ns) |
Modules or Types:
| Modules | Crystal Dimension | Application | Orientation Theta/Phi deg | Coatings |
| SHZGP-7515-54 | 7x5x15mm | OPO @ 2.1-> 3.5-5 µm | 54/0 | AR@2.1µm+BBAR@3.5-5µm |
| SHZGP-7520-54 | 7x5x20mm | OPO @ 2.1-> 3.5-5 µm | 54/0 | AR@2.1µm+BBAR@3.5-5µm |
| SHZGP-7525-54 | 7x5x25mm | OPO @ 2.1-> 3.5-5 µm | 54/0 | AR@2.1µm+BBAR@3.5-5µm |
Zinc germanium phosphide (ZnGeP2) is a promising mid-IR nonlinear crystal, exhibiting outstanding NLO properties. ZnGeP2 (ZGP) crystals have large nonlinear susceptibility (d36~75 pm/V), which is approximately 160 times that of KDP. ZGP crystals are also optically transparent over the 0.74–12μm wavelength region, with a relatively high laser damage threshold, and are therefore recommendable for producing tunable laser output in the near-infrared spectrum. ZGP Crystals could accommodate various applications including SHG, SFG, OPO, and OPG/OPA.
Applications of ZGP Crystals:
1. Second, third, and fourth harmonic generation of CO2 laser
2. Optical parametric generation (OPO) with pumping at wavelengths of 2.05-2.94μm and possibly the effective generation of 3-10μm light output
3. Producing coherent radiation in sub-millimeter-range from 70.0μm to 1000μm - terahertz range
4. Generation of combined frequencies of CO2 and CO laser radiation and other lasers working in the crystal transmission range
Curves:
%20Crystals75.jpg)
%20Crystals76.jpg)
