GSGG:Cr passive Q switches
Crystals with saturable absorption effect are used for making passive laser shutters (Q swithes). Such devices are widely used in solid state lasers development making its design more compact and cheap as compared to conventional EO or AO Q switches.
GSGG:Cr:Mg crystal is a new material for passive Q switching in a range near 1 mm.
Passive Q switches based on this crystal have operation parameters similar to that of well known YAG:Cr with some advantages such as transparency in visible range (simplifies the alignment procedure) and possibility to provide necessary initial transmission at less thickness (more compact laser design).
GSGG:Cr:Mg are well suited for application in short pulse diode pumped microchip lasers.
Properties of Cr, Mg doped GSGG crystals
Parameter |
Value |
Chemical Composition |
Gd3Sc2Ga3O12 |
Doping Ions |
Chromium (Cr4+)
Magnesium (Mg2+) |
Structure, space group |
Cubic, m3m (O10n) |
Lattice parameters, nm |
1.257 |
Density, g/cm3 |
6/5 |
Hardness (Mohs) |
7 |
Thermal conductivity, W/mk |
0.070 |
Heat capacity, J/gK |
0.448 |
Thermal coefficient of expansion, K-1 |
7.5 · 10-6 |
Refraction index at λ = 1.064 mm |
1.946 |
Absorption at λ = 1.064 mm, cm-1 |
0.2 10 |
Relaxation time of the exited state, ns |
200 |
Q switch standard specification
Operating wavelength range, nm |
950 1100 |
Initial transmittance, % |
5 95 |
Contrast |
6 10 |
Absorption cross section at λ = 1.06 mm, cm2 |
5 · 10-18 |
Minimum laser strength, J/cm2 |
> 5 |
Diameter, mm |
5 9 |
Thickness, mm |
0.5 - 5 |
Polish quality |
20/10 S/D |
Parallelism |
< 30 arc.sec. |
Flatness |
λ/8 |
AR coatings |
R < 0.2% @ 1064 nm |
|
