Optical pressure and temperature sensing properties of Nd 3+ :YTaO 4

The pressure- and temperature-dependent luminescence properties of M′-phase Nd 3+ :YTaO 4 synthesized by a molten salt method are presented. Ten near-infrared emission lines originating from the transitions between the two Stark levels R 1,2 of the 3 F 3/2 state and the five Stark levels Z 1,2,3,4,5 of the 4 I 9/2 state for the doped Nd 3+ ions can be clearly identified. All these emission lines are found to shift linearly with pressure in a range up to ∼11 GPa. The R 2,1 → Z 5 emission lines have larger pressure sensitivities, which are 16.44 and 14.27 cm −1 GPa −1 . The intensities of all the emission lines evolve with pressure non-monotonically, and peak at ∼1 GPa. The R 1 → Z 4,5 and R 2 → Z 1 emission lines can be obviously narrowed under the hydrostatic pressure, and broadened under the non-hydrostatic pressure, indicating their potential capability for reflecting the characteristic of a pressure environment. The intensity ratio of the R 2,1 → Z 5 emission lines exhibits a large temperature dependence, with a relative sensitivity between 0.129% and 0.108% K −1 in the physiological temperature range of 290–320 K. Thermal variations of the spectral positions and widths of the R 2,1 → Z 5 emission lines are also investigated. A high thermal stability for the position of the R 2 → Z 5 emission line is revealed. Based on the experimental results, the advantages and potential of Nd 3+ :YTaO 4 as a multi-functional sensor for pressure and temperature are discussed.