${\mathrm{Er}}^{3+}$-doped ${\mathrm{ZrO}}_2-\mathrm{C}\mathrm{a}\mathrm{O}$ eutectic crystals with ordered microstructure have been grown by the laser floating zone method. The microstructure consists of alternating 2 μm thick lamellae of calcia-stabilized zirconia (CaSZ) and ${\mathrm{CaZrO}}_3$ crystals. ${\mathrm{Er}}^{3+}$ enters both phases but at a higher concentration in CaSZ. Due to its higher refractive index, the latter phase acts as a light guiding medium. The optical properties of ${\mathrm{Er}}^{3+}$-doped eutectic, as well as its components, CaSZ and ${\mathrm{CaZrO}}_3$ crystals, are analyzed. Absorption and emission spectra of ${\mathrm{CaZrO}}_3$ consist of narrow bands. For this crystal most of the ${\mathrm{Er}}^{3+}$ Stark level positions are given. In contrast, the bands for CaSZ are broad, as it corresponds to a defective material. Absorption oscillator strengths, radiative-transition probabilities and emission lifetimes have been measured at different temperatures, between 600 and 4 K. Absorption oscillator strengths are 1.5 times higher for ${\mathrm{Er}}^{3+}$ in ${\mathrm{CaZrO}}_3$ than in CaSZ, while multiphonon deexcitation probabilities are one order of magnitude smaller, with the exception of the lowest energy ${}^4{I}_{13/2}{\to }^4{I}_{15/2}$ emission, which presents the maximum quantum efficiency in both phases.

• Received 19 June 1997

DOI:https://doi.org/10.1103/PhysRevB.56.10907