Neodymium doped Potassium-Gadolinium Tungstate crystals (Nd:KGd(WO4)2 or Nd:KGW) are low-threshold high effective laser medium exceptionally suitable for laser rangefinders. The efficiency of such lasers is 3 - 5 times better than that of the Yttrium-Aluminium Garnet (YAG) lasers. At low pumping energies (0.5 to 1.0 J) KGW crystals are one of the few materials ensuing an effective generation. KGW single crystals can also be used for the fabrication of high-efficiency lasers with high output energy. The single crystals exhibit a high optical quality. KGW crystals have great value of the bulk strength for laser radiation.
Properties of Nd:KGW laser crystal
Chemical Formula:
Nd3+M/sup>:KG(WO4)2
Crystal Structure:
Monoclinic; 2/m; l2/a
Lattice Constants:
a=8.087, b=10.374, c=7.588Å, β=94.4°
Melting Point:
1075°C; Phase transition to tetragonal form 1005 °C
Density:
7.27 g/cm³
Mohs Hardness:
4
Yong modules:
115.8[100], 152.5[010], 92.4[001]
Thermal Conductivity:
2.8[100]; 2.2[010]; 3.5[001] W/m/K
Nd:KGW Optical Properties
Transmission range:
350 ~5500nm
Refractive Index:
nq = 2.049; np = 1.978; nm = 2.014 @1067 nm
Lasing Wavelength:
911 nm 1067 nm 1351 nm
Peak Emission Cross Section:
>3.8 x 10-19/cm² @1067nm
Absorption Bands:
941 nm, 968.5 nm
Absorption bandwidth:
18nm for 940nm, 2nm for 969nm
Fluorescent lifetime::
110 µs (3% doping), 90 µs ( 8% doping)
Optical homogeneity:
1 x 10-5
Bend limits:
13.9[100], 10.2[010], 6.4[001] kg/mm
Solubility in water:
Insoluble
Optical damage threshold:
20 GW/cm²
General Specifications of Nd:KGW Laser Crystal
1) Orientation:
Custom specs, crystalline direction (+/-0.5°)
2) Max size:
Dia. 20 x 75mm
3) Surface quality:
better than 10/5 Scratch/Dig
4) Parallelism:
10 arc seconds
5) Perpendicularity:
5 arc minutes
6) Surface flatness:
λ/10 at 633 nm
7) Clear aperture:
Central 95%
8) Chamfer:
0.15mm @45°
9) Damage threshold:
over 20GW/cm² (without coating)
10) Coating: AR, HR or upon customer's specification
