Optical pressure and temperature sensing properties of Nd3+:YTaO4

The pressure- and temperature-dependent luminescence properties of M′-phase Nd3+:YTaO4 synthesized by a molten salt method are presented. Ten near-infrared emission lines originating from the transitions between the two Stark levels R1,2 of the 3F3/2 state and the five Stark levels Z1,2,3,4,5 of the 4I9/2 state for the doped Nd3+ ions can be clearly identified. All these emission lines are found to shift linearly with pressure in a range up to ∼11 GPa. The R2,1 → Z5 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 R1 → Z4,5 and R2 → Z1 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 R2,1 → Z5 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 R2,1 → Z5 emission lines are also investigated. A high thermal stability for the position of the R2 → Z5 emission line is revealed. Based on the experimental results, the advantages and potential of Nd3+:YTaO4 as a multi-functional sensor for pressure and temperature are discussed.