Multifunctional Pr³⁺:YPO₄ single crystals were investigated by high-resolution optical Fourier spectroscopy. The analysis of the transmission and luminescence spectra allowed us to supplement information on crystal-field levels of the Pr³⁺ ion. Shapes of spectral lines corresponding to transitions from the ground state to the degenerated Γ₅ crystal-field levels reveal the hyperfine structure and unambiguously point to the presence of random lattice deformations. The experimentally observed line shapes were successfully modeled and the halfwidth of the distribution function of random lattice deformations was determined. The lines with frequencies 4308 cm⁻¹ and 9680 cm⁻¹ are most sensitive to deformations and can be used to control the quality of YPO₄ single crystals intended for applications in modern quantum technologies.

通过高分辨率光学傅里叶光谱法研究了多功能Pr ³⁺：YPO ₄单晶。透射光谱和发光光谱的分析使我们可以补充有关Pr ³⁺离子的晶体场水平的信息。从基态到对应于转变谱线形状退化Γ ₅晶体场水平揭示的超精细结构和明确地指向无规晶格变形的存在。成功地模拟了实验观察到的线形，并确定了随机晶格变形的分布函数的半角。频率为4308 cm ^-1和9680 cm ^-1的线对变形最敏感，可用于控制旨在用于现代量子技术中的YPO ₄单晶的质量。