Yb:YAG is a diode-pumped laser gain material with broad pump absorption and a long upper-state lifetime. Reference designs compare its thermal loading and energy storage with Nd:YAG, with doping and geometry selected for the power regime.
Properties, applications and specifications
Yb:YAG is one of the most promising laser-active materials and more suitable for diode-pumping than the traditional Nd-doped systems. Compared with the commonly used Nd:YAG crsytal , Yb:YAG crystal has a much larger absorption bandwidth to reduce thermal management requirements for diode lasers, a longer upper-laser level lifetime, three to four times lower thermal loading per unit pump power. Yb:YAG crystal is expected to replace Nd:YAG crystal for high power diode-pumped lasers and other potential applications.
In the specific case of the host material YAG, Yb3+ has a storage lifetime of 950 µs and a quantum defect of only 8.6%. Yb3+:YAG also has a broad pump line at 940 nm that is 10 times broader than the 808 nm pump line in Nd3+YAG making the system less sensitive to thermal drift of the pump diodes wavelength. These material properties combined with the development of robust long-lifetime InGaAs pump diodes at 940 nm have made this material a superior candidate for diode-pumped high-energy lasers.
Crystals of Yb 3+ doped YAG are available in a variety of dopant concentrations from 1% - 100% (e.g. Ytterbium aluminum garnet - YbAG).
Advantages:
1. High optical quality 2. Very high slope efficiency 3. Very low fractional heating, less than11% 4. No excited-state absorption or up-conversion 5. Broad absorption bands, about 8nm@940nm 6. High thermal conductivity and large mechanical strength 7. Conveniently pumped by reliable InGaAs diodes at 940nm(or 970nm)
Specifications
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Dopant concentration
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Yb:0.3~15at%
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Orientation
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[100]or[111]within 5°
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Wavefront Distortion
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≤0.125λ/inch
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Extinction
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≥28dB
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Rod Sizes
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Diameter: 2~20mm, length: 5~150mm Upon request of customer
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Dimensional Tolerances
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Diameter: +0.00/-0.05mm, length:±0.5mm
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Barrel Finish
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Ground Finish with 400# grit or polished
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Parallelism
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≤10”
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Perpendicularity
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≤5’
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Flatness
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Surface Quality
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10-5(MIL-O-13830A)
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Chamfer
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0.15±0.05mm
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AR Coating Reflectivity
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≤0.25%(@1030nm)
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Damage Threshold
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500MW/cm210ns 1Hz at 1064nm
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Main Properties of Yb:YAG crystal:
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Chemical Formula
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Yb3+:Y3AI5O12
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Laser Wavelength
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1030nm
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Fluorescence Lifetime
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1.2 ms
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Index of Refraction
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1.82
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Loss Coefficient
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0.003 cm-1
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Crystal Structure
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Cubic
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Lattice Parameters
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12.01 Å
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Melting Point
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1970℃
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Moh Hardness
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8.5
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Density
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4.56±0.04g/cm3
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Specific Heat (0-20)
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0.59J/g.cm3
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Thermal Expansion Coefficient
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[111]Direction:7.8×10-6/℃(0~250℃)
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Thermal Conductivity
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14W/m/K(@20℃) , 10.5W/m/K(@100℃)
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Standard Products
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Part No
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Diameter(mm)
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Length(mm)
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Doping
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Cut angle
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Coating
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YbYAG-1510-20
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15
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1
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20%
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<111>
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AR/AR1030 nm
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YbYAG-1510-15
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15
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1
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15%
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<111>
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AR/AR1030 nm
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YbYAG-1205-20
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12.7
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0.5
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20%
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<111>
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AR/AR1030 nm
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YbYAG-1205-15
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12.7
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0.5
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15%
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<111>
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AR/AR1030 nm
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