ZGP (ZnGeP2) Crystals
ZnGeP2 (zinc germanium phosphide) crystals have a number of good properties, and is in the infrared nonlinear crystal. The nonlinear susceptibility of ZnGeP2 (ZGP) crystal is about 160 times that of KDP (d36~75 pm/V). ZGP shows good optical transparency at 0.74-12 mm, and has a relatively high laser damage threshold, so it is very suitable for the production of near-infrared tunable lasers. ZGP is a very promising material for mid-infrared equipment such as SHG, SFG, OPO and OPG/OPA.
Feature
Wide transmission region from 0.74μm to 12μm
Large nonlinear coefficient
Phase matchable over a broad spectral region
Applications: SHG, SFG, OPO and OPG/OPA in the mid-infrared region
Applications:
Second, third, and fourth harmonic generation of CO2 laser
Optical parametric generation (OPO) with pumping at a wavelength of 2.05-2.94μm and the possibility to generate effectively 3-10μm ranges
Second-harmonic generation of CO-laser
Producing coherent radiation in sub-millimeter-range from 70.0μm to 1000μm - terahertz range
Generation of combined frequencies of CO2- and CO-lasers radiation and other lasers are working in the crystal transparency region
Specifications:
| Materials |
ZnGeP2 crystals |
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 |
| ZGP-7515-54 |
7x5x15mm |
OPO @ 2.1-> 3.5-5 µm |
54/0 |
AR@2.1µm+BBAR@3.5-5µm |
| ZGP-7520-54 |
7x5x20mm |
OPO @ 2.1-> 3.5-5 µm |
54/0 |
AR@2.1µm+BBAR@3.5-5µm |
| ZGP-7525-54 |
7x5x25mm |
OPO @ 2.1-> 3.5-5 µm |
54/0 |
AR@2.1µm+BBAR@3.5-5µm |