Yb:KGW Laser Crystal
Yb:KGW crystals are Ytterbium-doped Potassium Gadolinium Tungstate crystals.
They have a broad emission spectral band from 1023-1060nm, and are capable of generating short (ps or fs) laser pulses.
The broad absorption spectrum at 980nm and high absorption rate of pump radiation allow for efficient use of diode laser pumping.
Compared to YAG used as a host for Yb3+, KGW has the advantage of a larger absorption cross-section and reduced minimum pump intensity needed to achieve transparency in the Ytterbium quasi-two level system.
Yb:KGW crystals are excellent materials that emit lasers over a wide spectral range and enable high efficiency laser oscillation.
Basic Properties
| Crystal Structure | monoclinic |
|---|---|
| Point Group | C2/c |
| Cell Parameters | a = 8.09 Å; b = 10.43 Å; c = 7.588 Å β = 94.4° |
| Refractive index, at 1067 nm | nq = 2.033; np = 2.037; nm = 1.986 |
| Mohs Hardness | 5 |
| Density, g/cm3 | 7.27 |
| Melting Point | 1075℃ |
| Thermal Conductivity at 373°K, W × cm-1 × K-1 | K[100] = 0.026; K[010] = 0.038; K[001] = 0.034 |
| Termal Expansion Coefficient, at 373 K |
α[100] = 4 × 10-6 × °K-1; α[010]= 1.6 × 10-6 × °K1; α [001]= 8.5 × 10-6 × °K-1 |
| Lasing Wavelength | 1023～1060 nm |
| Absorption Band | 981 nm (FWHM 3.7 nm) |
| Fluorescent Lifetime | 600 µs (5 % doping) |
Specifications of Yb:KGW
| Orientation | [010] |
|---|---|
| Standard Dopant Concentration (at. %) | 5% |
| Maximum Length | 50 mm |
| Length Tolerance, mm | +1.0 / -0.0 |
| Diameter Tolerance, mm | +/- 0.1 |
| Parallelism | <30″ |
| Perpendicularity | <15' |
| Surface Quality | 20/10 |
| Coating | AR-coated |