Description
Co Spinel Q Switch Crystals
Passive Q-switches or saturable absorbers generate high power laser pulses without the use of electro-optic Q-switches, thereby reducing the package size and eliminating a high voltage power supply. Co2+:MgAl2O4 is a relatively new material for passive Q-switching in lasers emitting from 1.2 to 1.6μm, in particular, for eye-safe 1.54μm Er:glass laser, but also works at 1.44μm and 1.34μm laser 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 ratio of Q-switch, i.e. the ratio of initial (small signal) to saturated absorption is higher than 10.
Absorption Spectrum of Co:Spinel crystal
Absorption Spectrum of Co:Spinel crystal
Transmission Spectrum of Co:Spinel crystal
Features
• Suitable for 1540 nm eye-safe lasers
• High absorption section
• Negligible excited state absorption
• High optical quality
• Uniformly distributed Co
Parameters
|
Property |
Value |
|
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 |
|
Specific Heat/ (J·g-1·K-1) |
1.046 |
|
Thermal Expansion /（10-6 /°C@25°C ） |
5.9 |
|
Hardness (Mohs) |
8.2 |
|
Extinction Ratio |
25dB |
|
Orientation |
[100] or [111] < ±0.5° |
|
Optical density |
0.1-0.9 |
|
Damage Threshold |
>500 MW/cm2 |
|
Doping concentration of Co2+ |
0.01-0.3 atm% |
Specifications
|
Property |
Value |
|
Concentrations |
(0.05~0.35) wt% |
|
Absorption coefficient |
0 ～ 7 cm-1 |
|
Ground-state absorption cross-section σGSA(E-19 cm2) |
2.8（±0.4）@1340nm |
|
Excited state absorption cross-section σESA (E-20 cm2) |
2.0（±0.6）@1340nm |
|
Ground-state absorption cross-section σGSA(E-20 cm2) |
3.5（±0.4）@1540nm |
|
Excited state absorption cross-section σESA (E-20 cm2) |
1.0（±0.6）@1540nm |
|
Working wavelength |
1200 – 1600 nm |
|
End Configuration |
Flat/Flat |
|
Figure of Merit(FOM) |
100~300 |
|
Coatings |
AR/AR@1540，R<0.2%; AR/AR@1340，R<0.2% |
Polishing Specification
|
Property |
Value |
|
Orientation Tolerence |
< 0.5° |
|
Thickness/Diameter Tolerance |
±0.05 mm |
|
Surface Flatness |
<λ/8@632 nm |
|
Wavefront Distortion |
<λ/4@632 nm |
|
Surface Quality |
10/5 |
|
Parallel |
10〞 |
|
Perpendicular |
5ˊ |
|
Clear Aperture |
>90% |
|
Chamfer |
<0.1×45° |
|
Maximum dimensions |
Dia(3-15)×(3-50)mm |
Standard products
|
Initial transmission @1064nm |
Dimensions，mm |
Coatings |
Surface Flatness |
Surface Quality (scratch/dig) |
|
T0=30% |
dia 5 |
AR≤0.2% @1340nm Or AR≤0.2% @1540nm
|
<λ/8@632 nm |
10/5 |
|
3x3 |
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|
5x5 |
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|
T0=40% |
dia 5 |
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3x3 |
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5x5 |
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T0=50% |
dia 5 |
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3x3 |
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5x5 |
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T0=60% |
dia 5 |
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3x3 |
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5x5 |
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|
T0=70% |
dia 5 |
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3x3 |
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5x5 |
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|
T0=80% |
dia 5 |
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3x3 |
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5x5 |
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|
T0=85% |
dia 5 |
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|
3x3 |
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5x5 |
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|
T0=90% |
dia 5 |
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3x3 |
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5x5 |
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|
T0=95% |
dia 5 |
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|
3x3 |
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5x5 |
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|
T0=97% |
dia 5 |
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|
3x3 |
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|
5x5 |
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