Optical characteristics of Cr3+ and Nd3+ codoped Y3Al5O12 ceramics

The optical characteristics of Cr3+Cr3+ and Nd3+Nd3+ codoped Y3Al5O12Y3Al5O12 (YAG) ceramics are measured. These measurements are done using two pumping sources, a 808 nm laser diode (LD) and a Xe short-arc lamp, to simulate solar radiation. The specimens used are 0.1%Cr3+/1.0%Nd3+0.1%Cr3+/1.0%Nd3+ and 3.0%Cr3+/1.0%Nd3+3.0%Cr3+/1.0%Nd3+ (atomic%) codoped YAG ceramics. A Nd:YAG crystal doped with 1.0%Nd3+1.0%Nd3+ is used as a reference. The saturation intensities of the Cr/Nd:YAG ceramics pumped by the LD are the same as that of the Nd:YAG crystal, while they are higher when they are pumped by the Xe lamp. The saturation intensities are 3.23±0.18kW/cm2 for the 0.1%0.1% Cr-doped ceramic and 4.30±0.24kW/cm2 for the 3.0%Cr-doped ceramic. The small signal gains of the 0.1%Cr-doped and 3.0%Cr-doped ceramics are measured and found to be 1.8 times and 7.0 times higher than that of Nd:YAG for the same intensity of solar pumping, respectively. The quantum efficiency of energy transfer from Cr3+Cr3+ to Nd3+Nd3+ is estimated to be 0.88±0.090.88±0.09 for the 0.1%Cr-doped ceramic and 0.67±0.080.67±0.08 for the 3.0%Cr-doped ceramic.