Laser ceramics with disordered crystalline structure

New ceramic materials based on yttrium oxide $\mathrm{Y}_2\mathrm{O}_3$ with isovalent ($\mathrm{Yb}_2\mathrm{O}_3$, $\mathrm{Nd}_2\mathrm{O}_3$, and $\mathrm{Lu}_2\mathrm{O}_3$) and heterovalent ($\mathrm{ZrO}_2$ and $\mathrm{HfO}_2$) components are synthesized, and their spectroscopic properties are investigated. Possible channels of losses in the gain of stimulated radiation in the radiative transitions of $\mathrm{Nd}^{3+}$ and $\mathrm{Yb}^{3+}$ ions in ceramics with heterovalent additives are studied. The results of measurements of $\mathrm{Y}_2\mathrm{O}_3$ ceramics doped with zirconium and hafnium ions, the emission bandwidth and the lifetimes of the ${}^4\mathrm{F}_{3/2}$ and ${}^2\mathrm{F}_{5/2}$ levels of $\mathrm{Nd}^{3+}$ and $\mathrm{Yb}^{3+}$ ions, respectively, are presented. It is shown that the nonradiative population of the ${}^4\mathrm{F}_{3/2}$ levels of neodymium ions is due to their dipole-dipole interaction with $\mathrm{Zr}^{3+}$ and $\mathrm{Hf}^{3+}$ ions. Laser generation in [($\mathrm{Yb}_{0,01}\mathrm{Lu}_{0,24}\mathrm{Y}_{0,75})_2\mathrm{O}_3]_{0,88}(\mathrm{ZrO}_2)_{0,12}$ ceramics with disordered crystalline structure was achieved at a wavelength of $1034$ nm with a differential efficiency of $29\%$.