Gadolinium scandium gallium garnet(GSGG) codoped with Cr is a laser material with high efficiency. An electro-optic shutter element was first utilized to provide Q-switched operation of the ruby laser. Passive Q-switched ruby lasers were achieved with saturable dye absorbers and colored glass (compounds of selenium and cadmium sulfide. Recently the operational characteristics of a dye Q-switch for a pulsed ruby laser was still studied for application in underwater holography. However, the dye Q-switch was limited in durability because of degradation (decomposition) of the dyes and the glass Q-switch was readily damaged. Thus, the tetravalent chromium doped gadolinium scandium gallium garnet Gd3Sc2Ga3O12 (Cr4+: GSGG) passive Q-switch ruby laser-offers for the first time high reliability, durability and high efficiency.
Cr:GSGG crystal – a crystal which shows high efficiency and high reliability.
Cr4+: GSGG has been utilized for the first time to provide a saturable absorber Q-switch for the ruby laser. Single output pulse operation (100 mJ and 27 ns duration) with efficiencies relative to the free-running ruby laser operation of 25-30% was routinely obtained. The crystalline material GSGG:Cr3+ is currently of interest as a broad-band, room temperature laser material. The small separation between the 4T2 and 2E electronic levels of Cr3+ in the system can result in interesting spectroscopic behaviour. People have investigated the temperature dependence of the CW and transient luminescence, and have found it to be consistent with a model for the dominant Cr3+ site in which the lowest energy 2E and 4T2 levels are approximately coincident in energy at low temperature.
|Emission wavelength (nm)||1061.2|
|Emission cross section (pm2)a||13|
|R2->Y3 transition linewidth (cm-1)||11.5|
|Nd3+ fluorescence lifetime (ps) at low concentrations (<1017cm-3 )||273-283|
|Nd3+ concentration for which lifetime is reduced by 50% (1020 Nd ions cm-3)||5|
|Refractive index at 1064 nm||1.9424|
|Index change with temperature, dn/dt,(10-6 k-1)||10.9|
|P11||-0.012 ± 0.003|
|P12||0.019 ± 0.003|
|P44||-0.0665 ± 0.0013|
|Heat capacity (J*g-1*K-1)||0.4029|
|Thermal conductivity (W*m-1*K-1)||6|
|Thermal expansion (10-6 K-1)||7.5|
|Young’s modulus (GPa)||210|
|Fracture toughness (MPa )||1.2|
|Thermal- stress resistance (W*m-1)b||660|
Strong and saturable absorption
Good thermal conductivity
Cr4+: GSGG used in saturable absorber Q-switch for the ruby laser:
The tetravalent chromium doped gadolinium scandium gallium garnet Gd3Sc2Ga3O12 (Cr4 + : GSGG) passive Q-switch ruby laser-offers for the first time high reliability, durability and high efficiency. Single output pulse operation (100 mJ and 27 ns duration) with efficiencies relative to the free-running ruby laser operation of 25-30% was routinely obtained.