Optical Spectra and Energy Levels of Erbium-Doped Yttrium Orthoaluminate

The absorption and emission spectra of YAlO₃:Er³⁺ were recorded photographically in the spectral region 12 000–40 000 cm⁻¹. Catalogs of the absorption and emission lines are presented; line strength data are given for the absorption lines. From these spectra, 104 energy levels of YAlO₃:Er³⁺ from 0 to 40 000 cm⁻¹ were deduced and are presented. These comprise the crystal field components of 22 of the 24 Er³⁺ free ion levels occurring below 40 000 cm⁻¹. A free ion calculation was carried out. The free ion parameters that minimize the rms deviation between calculated and observed centers of gravity are $E^1{\text{=6786.3,\hspace{0.17em}E}}^2{\text{=32.415,\hspace{0.17em}E}}^3\text{=643.27,\hspace{0.17em}ζ=2380.7,\hspace{0.17em}α =21.721,\hspace{0.17em}β =−683.43}$ , and γ=389.03 cm⁻¹. Reasons for the absence of the ²P_1/2 and ⁴G_5/2 lines from the absorption data are discussed.