Laser rods - Ytterbium doped
Yb:YAG
The Yb3+ ion exhibits a small quantum defect and a quasi-three level system with a long upper laser level lifetime, which is important for energy accumulation in Q-switched lasers.
The wide luminescence band of Yb3+ is advantageous for the generation of sub-picosecond pulses. Long energy storage lifetime, broad absorption band at 940 nm and very low quantum defect make Yb:YAG crystal superior candidate for diode-pumped high-energy lasers.
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| Material characteristics | |
|---|---|
| Crystal structure | cubic - la3d |
| Emission wavelength | 1030 nm |
| Pump bands | 941 nm, 969 nm |
| Refractive index at 632 nm | 1.83 |
| Absorption cross section at 940 nm | 8.2 x 10-21 cm2 |
| Emission cross section at 2013 nm | 2.1 x 10-20 cm2 |
| Design | |
| Rod or disc diameters | 2 – 80 mm |
| Rod length or disc thickness | 0.1 - 100 mm |
| Doping concentration | 1 – 10 at.% |
| Polishing | Barrel surface fine ground or polished. Perpendicular or wedged ends. Polishing according to DIN and MIL standards. |
| Coatings | HfO2 based high reflectors, output couplers or antireflective coating |
Application example: Q-Switched Yb:YAG-Cr:YAG microchip laser
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The Yb:YAG/Cr:YAG microchip laser threshold pumping power was found to be 3.3 W. With the increasing pumping power the mean output power, and generated pulse repetition rate also increased up to 1 W and 13.6 kHz, respectively, for the pumping power 9.3 W. The maxim output power was reached without observable thermal roll-over. |
| The laser slope efficiency in respect to incident pumping power was ≈ 17 %. The average pulse width was 1.58 ± 0.04 ns. The maximum pulse energy and peak power value were 73.8 ± 0.7 µJ, and 46.0 ± 0.8kW, respectively. |  |
Related download
Yb:YAG disc
Yb:YAG in large-area, high-energy diode-pumped lasers
Yb:LuAG
Yb:LuAG is very promising Yb-doped laser material. The optical and mechanical properties of LuAG are very similar to YAG crystal. Thanks to similar atomic weight and ionic size of doping Yb3+ ions and substituted Lu3+ lattice ions, the doping concentration has a low influence on lattice vibration modes of LuAG which allow to obtain highly doped Yb:LuAG laser crystal without significant influence on thermal conductivity of this material.
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| Material characteristics | |
|---|---|
| Crystal structure | cubic - la3d |
| Emission wavelength | 1031 nm |
| Pump bands | 940 nm, 968 nm |
| Refractive index at 632 nm | 1.84 |
| Absorption cross section at 938 nm | 7.2 x 10-21 cm2 |
| Emission cross section at 2031 nm | 2.6 x 10-20 cm2 |
| Design | |
| Rod and disc diameters | 2 – 20 mm |
| Disc thickness or rod length | 0.1 – 100 mm |
| Doping concentration | 1% - 10% at. |
| Polishing | Barrel surface fine ground or polished. Perpendicular or wedged ends. Polishing according to DIN and MIL standards. |
| Coatings | HfO2 based high reflectors, output couplers or antireflective coating |
1 K. Beil, S. T. Fredrich-Thornton, R. Peters, K. Petermann, and G. Huber, “Yb-doped thin-disk laser materials: A comparison between Yb:LuAG and Yb:YAG,” in Advanced Solid-State Photonics 2009 Technical Digest on CD-ROM, WB28, OSA, 2009.
