The effect of Cr concentration on emission cross-section and fluorescence lifetime in Cr,Yb:YAG crystal

The emission cross-section, and fluorescence lifetime of Cr,Yb:YAG with different concentration of Cr4+ and Yb:YAG were measured. With the increase of Cr concentration in Cr,Yb:YAG, the emission cross-section keeps constant and fluorescence lifetime decreases. The quantum efficiency decreases and the energy transfer efficiency from Yb3+ to Cr4+ increase as the Cr concentration increases in Cr–Yb-co-doped Cr,Yb:YAG system. The nonradiative Yb3+→Cr4+ energy transfer is consistent with an electric dipole–dipole interaction mechanism. The optimum Cr concentration for Cr,Yb:YAG was estimated. Also the potential of Cr,Yb:YAG as a self-Q-switched laser crystal was discussed.