Effect of Gd3+/Ga3+ on Yb3+ emission in mixed YAG at cryogenic temperature

We investigated the effect of Gd3+ and Ga3+ on Yb:YAG emission at cryogenic temperatures by preparing ceramic pellets by solid state reaction method with different Gd3+ and Ga3+ content. Incorporation of Gd3+ shows only a small effect on spectral broadening whereas incorporation of Ga3+ in Yb:YAG results in significant broadening. Such an inhomogeneous broadening is due to the replacement of larger Ga3+ ion in two different cationic sites of Al3+ which causes a change in local crystal field on the Yb3+ site.