Passive Q-Switch Crystal Cr:YAG Overview: Cr4+:Y3Al5O12 crystal (Cr4+:YAG) is one of the most promising passive Q-switching materials
for passively Q-Switching diode pumped or lamped Nd or Yb doped
lasers at wavelength from 0.8 to 1.2um. Because of Cr4+:YAG's
chemical stability, durability, UV resistance, good thermal
conductivity, high damage threshold (> 500 MW/cm ) and easy
operation, Cr4+:YAG will replace some traditional switching
materials, such as LiF and organic Dye. The preliminary experiments
of Cr:YAG showed that the pulse width of passively Q-switched
lasers could be as short as 9ns for diode pumped Nd:YAG lasers and
repetition rate as high as 10kHz for diode pumped Nd:YVO4 lasers. General Specifications Of Cr4+:YAG: | Material | Cr4+:YAG | | Orientation | <111> or <110> or <100> | | Initial absorption coefficient | 0.5-7/cm@1064nm | | Diameter tolerance | Diameter:+0/-0.02mm, W×H:+/-0.1mm | | Length tolerance | +/-0.5mm | | Initial transmittance | 5%-95%@1064nm | | Dimension | Diameter:3-12mm, H×W:2×2-30×30mm (upon customer’s request) | | Barrel finish | Ground finish 400#Grit | | Clear aperture | >90% central area | | Parallelism | <10 arc seconds | | Perpendicularity | <5 arc minutes | | Flatness | <λ/8@632.8nm | | Scratch/Dig | 10/5@MIL-0-13830A | | Anti-Reflection coating | R<0.15%@1064nm per surface | | Damage threshold | >750MW/cm2@1064nm 10ns 10HZ |
Physical and Optical Properties of Cr4+:YAG: | Crystal Structure | Cubic | | Dopant | 0.5~3% Cr | | Wavelength | 950nm-1100nm | | Melting Point | 1970℃ | | Curie Point | 936℃ | | Density | 4.56g/cm3 | | Mohs Hardness | 8.5 | | Recovery Time | 8.5us | | Thermal Conductivity | 12.13W/m/K | | Loss Coefficient | 0.003cm-1 | | Refractive Index | 1.82 @1064nm | | Base State Absorption Cross Section | 4.3x10-18/cm2 | | Emission State Absorption Cross Section | 8.2x10-19/cm2 | | Fluorescence Lifetime | 3.4us | | Optical Damage Threshold | >500MW/cm2 |
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