Description:
Co2+:MgAl2O4 Cobalt-doped magnesium aluminate spinel
Co2+:MgAl2O4 Cospinel is a relatively new material for passive Q-switching in lasers emitting from 1.2 to 1.6 μm, in particular, for eye-safe 1.54 μm Er:glass laser, but also works at 1.44 μm and 1.34 μm wavelengths. Spinel is a hard, stable crystal that polishes well. Cobalt substitutes readily for magnesium in the Spinel host without the need for additional charge compensation ions. High absorption cross section (3.5×10-19 cm2) permits Q-switching of Er:glass laser without intracavity focusing both with flash-lamp and diode-laser pumping. Negligible excited-state absorption results in high contrast of Q-switch, i.e. the ratio of initial (small signal) to saturated absorption is higher than 10.
Main applications:
- Passive Q-switch for Radar and RangingEr:Glass lasers @1,35µm
- Passive Q-switch for Medical lasers @1,500µm
Advantages:
- Rare excited absorption
- High constant of Q-switch
- High absorption section
- Long excited lifetime
- Evenly distributed cobalt
- Wide absorption band
Basic properties of Cospinel
| Chemical formula | Co2+:MgAl2O4 |
| Crystal structure | Cubic |
| Lattice parameters | 8.07Å |
| Density | 3.62 g/cm3 |
| Melting Point | 2105°C |
| Refractive Index | n=1.6948 @1.54 μm |
| Thermal Conductivity/(W·cm-1·K-1@25°C) | 0.033W |
| Thermal Expansion /（10-6 /°C@25°C ） | 1.046 |
| Specific Heat/ (J·g-1·K-1) | 5.9 |
| Hardness (Mohs) | 8.2 |
| Extinction Ratio | 25dB |
| Density | 1.6-1.75 |
Cospinel specifications:
| Orientation: | <100> or <111> |
| Initial absorption coefficient | 0~7cm-1@1064nm |
| Initial transmission | 50%~99% |
| Wavefront Distortion: | λ/8per inch @ 632.8 nm |
| Surface Quality: | 20/10 Scratch/Dig MIL-O-1380A |
| Parallelism: | < 10″ |
| Perpendicularity: | < 10′ |
| Clear Aperture: | > 90% |
| Surface Flatness: | < λ/10 @ 632.8 nm |
| Chamfer: | < 0.1 mm @ 45deg. |
| Size | Upon customer request |
| Coating | AR/HR/PR coating upon customer’s request |
| Damage Threshold | 750MW/CM2 at 1064nm, TEM00, 10ns, 10Hz |
| Quality Warranty Period | One year under proper use |
