Yb CaF2 Laser Crystals
Description
Due to the toughness and the flexible and cheap production process, CaF2 has been used in many substrate materials for laser crystals. As an amplifying ion, Yb3+ also allows a three-level laser scheme, leading to low quantum defects and a significantly longer fluorescence lifetime. Yb3+:CaF2 can also provide a high optical efficiency and high output powers due to the reduced thermal load. Recently, ytterbium-doped alkaline-earth fluoride is mostly used in diode-pumped femtosecond laser and amplifiers. Alkaline-earth fluorides which can be easily grown by using the standard Czochralski or Bridgman technique show a great potential in the wide transmission range, high damage threshold and low dispersion behavior.
Absorption Spectrum of Yb3+:CaF2 crystal
• Low quantum defect
• High damage threshold, good thermal conductivity
• Long fluorescence lifetime
• Low dispersion behavior
• Broad absorption bandwidth
• Limited nonlinear effects under intense laser irradiation
Applications
• High power ultrafast thin-disk oscillators
• Passively mode-locked oscillators
• Solid state tunable laser
Chemical and physical properties
Property | Value |
Chemical formula | Yb3+:CaF2 |
Crystal structure | cubic |
Lattice parameters, Å | 5.462 |
Orientation | [111] or [100] < ±0.5° |
Mass density | 3.18 g/cm3 |
Mohs hardness | 4 |
Young's modulus | 146 GPa |
Tensile strength | 2 GPa |
Melting point | 1418°C |
Thermal conductivity | 9.71 |
Specific Heat/ (J·g-1·K-1) | 0.8876 |
Thermal Expansion /（10-6/°C @25°C） | (16.5...19.4) |
Thermal shock resistance parameter | 800 W/m |
Refractive Index @ 1064 nm | 1.2996 |
Optical properties
Property | Value |
Optical Density | 0.1 to 0.8 |
Fluorescence lifetime | 2.4ms |
Concentrations | 0.5 mol % ~ 30 mol % |
Emission wavelength | 1015 nm ~ 1060 nm |
Absorption Coefficient | 1.0 cm-1 ~ 7 cm-1 |
Ground state absorption cross section | 0.8x10-20 cm2 |
Emission state absorption cross section: | 2.2x10-20 cm2 |
Transmission | 10% to 90% |
Coatings | AR≤ 0.2% @1030nm |
Damage Threshold: | > 500 MW / cm2 |
Polishing Specification
Property | Value |
Orientation Tolerence | < 0.5° |
Thickness/Diameter Tolerance | ±0.05 mm |
Surface Flatness | <λ/8 @632 nm |
Wavefront Distortion | <λ/8 @632 nm |
Surface Quality | 10/5 |
Parallel | 10〞 |
Perpendicular | 15ˊ |
Clear Aperture | >90% |
Chamfer | <0.1×45° |
Maximum dimensions | 2*2-15*15 mm×20mm |
Standard products
Material | Dimensions，mm | Coatings |
dia 5 | AR≤ 0.2% @1030+940nm | |
3x3 | ||
6x6 | ||
dia 5 | ||
3x3 | ||
6x6 |