Phase transition of YPO4 crystal induced splitting of 5D0→7F1 of doped Eu3+

For the first time, we investigated the crystal field dependent fine structure splitting in different crystal phases (pure tetragonal (T), pure hexahedral (H), (H + T) and (T + H)) of Eu3+:YPO4 crystals. We observed that each phase with its unique point group site symmetry results in unique fine structure splitting. The fine structure of T-phase and H-phase splits into two- and three-energy levels, respectively. By controlling temperature, the influence of dressing-phonon competition on the linewidth of spectral signal is also discussed. In T-phase Eu3+:YPO4, one spectral peak splits into three peaks under the action of stress and dressing field as temperature is reduced from 300 K to 77 K. The relationship between temporal and spectral intensity in different phases of Eu3+:YPO4 is also discussed. The Pr3+ ion has a stronger dressing than the Eu3+ ion in a host material of YPO4 which can be explained from higher dipole moment. To further explore this comparison, we investigated intensity-noise correlation under nonlinear phase controlled by time delay in both Eu3+:YPO4 and Pr3+:YPO4.